1. introduction
Contents
1. MR1200 RADIO MODEM 1200 bauds USER MANUAL 908709 02 AUGUST 2000 Table of contents 1 INTRODUCTION Io DOCE 5 pM INSTALLATION EE RE 7 2 T UPREAMBEE A DNI ied Lords tie neck Eie IUE RO 7 2 2 BXTERNAPEDESCRIPTION eee eco cot eee eet eee eee ee one eve eae eee e Dev e Oe eee ee cov iaa 7 2 3 CONNECTING TO THE TERMINAL eei eR SEO DEPO RERO Ps ir o re er Eon 8 2 4 CHOICE OF RADIO CHANNEL DATA TRANSMISSION RATE enne ener enne 9 2 5 POWER SUPPLY CONNECTION 4gvecexe seite uod ORE noi ie dd 9 2 6 CONNECTING TO THE TRANSCEIVER ics e sce g cepere re Ee E PR Ne eee Pie a eee e E Pene 9 2 6 1 Description of the LF interface signals esses eene eene nennen 9 2 6 2 The type of connecting cable to use essere ener 13 2 0 3 F aetory pressettitigsi o t tet e eu t eme teen 14 2 6 4 Particularity of the 2400 b s version sse eee eene eene trente 14 2 POWER SAVING FEATURE SET UD cedente e etre eR Dd ERO Ric ire e wan 15 2 8 CONNECTING THE OPTIONAL MICROPHONE LOUDSPEAKER SET s scsesssesssseseseseseseseeeneseneneeeeeeeeees 16 2 6 1 Description of the microphone loudspeaker interface sse 16 2 8 2 PTT connection push to talk essent ener nente entrent 16 2 8 3 Microphone connection esee eene trennen trente tren tne trennen enne 17 2 09 F R POWER SUPPLY o e to daft te dat delta dota 17 3 CONFIGURATION cE OR2. Straps S3 and S4 are factory set for a positive DP signal In the opposite case straps S3 and S4 need to be altered Once the copper tracks component side connecting the S3 pins and those between the S4 pins have been cut straps are soldered into position as shown below SET RS232 2 6 2 The type of connecting cable to use ETIC MR1200 USER MANUAL 908709 02 Page 13 Installation The connection between the MR1200 and the transceiver must be made using a short length of multicore screened cable The screen should be connected to the metal shell of the 15 way sub D connector 2 6 3 Factory pre setting ETIC can deliver modems pre configured for the chosen transceiver Interconnection wiring sheets have been produced for most models of transceiver on the market When ordering specify the make and type of transmitter include the FR02 option in the order modem set up if the transmitter details are not known to us option FRO3 should also be ordered transmitter connection investigation and 2 units with manuals forwarded which will enable a connection and line up adjustment sheet to be drawn up 2 6 4 Particularity of the 2400 b s version FFSK modulation at 2400 b s For FFSK modulation at 2400 b s the sub carriers coding bits 1 and 0 are respectively F1 1200 Hz and F0 2400 Hz Now 2400 b s is at the limit of
3. Configuration This parameter determines the length of time after which the MR1200 goes to sleep once transmission and reception of data has ceased de 0001 to 6000 MMSS 0000 MM minutes 2 ASCII numbers SS seconds 2 ASCII numbers The value 0000 prevents the modem from going to sleep 3 4 5 Other parameters Parameter 050 tp emi Fixes a limit to the length of the MR1200 s transmission time serving to avoid both a modem monopolising the radio channel and the risk of transceiver RF stages overheating from1to255 xls A value of 0 removes all limits on the duration of transmission Parameter 051 tp_sil A minimum period of post transmission silence can be defined to allow other MR1200 modems the time to access to the radio channel de 1 to 255 0 6 20 x duration of transmission The MR1200 ignores this parameter if no transmission time limit has been set parameter tp emi null Parameter 052 tp ae Corresponds to the length of time the MR1200 will wait before ending radio transmission once there is no more data to be sent de 0 to 255 1 20 ms Enter a low value 20 ms where applications function by a rapid exchange of data with brief request response intervals Enter a higher value 100 ms or more where data messages are long the control terminal s transmission speed is less than 2400 bits s data flow is irregular ETIC MR1200 USER MANUAL 908709 02
4. Note Should interference occur on the radio channel while the modems are synchronising several frames may be lost without this fact being signalled to the terminal Parameter 016 ges dsr With this parameter set to 1 the RS232 interface 107 DSR circuit is implemented as per a standard telephone line modem 107 DSR is ON during communication radio channel and OFF when at rest Setting its value to 0 forces 107 DSR to the permanently ON condition 107 DSR handling Hors c no permanently ON yes ON in communication 3 4 2 Configuring the radio interface Parameter 020 mod rad Defines the MR1200 data transmission mode 0 simple mode no CRC basic mode with CRC Modem transmission normally operates in basic mode the data is formatted into frames protected by the addition of a cyclic redundancy check code CRC resulting in a useful radio channel data rate of 900 b s Simple mode should only be used over a good quality radio link communicating stations relatively close and when it is essential to have a useful radio channel data rate greater than 900 b s Data 1s transmitted with no extra coding and any errors are no longer filtered on reception Parameter 021 tp alt ETIC MR1200 USER MANUAL 908709 02 Page 23 Configuration When the transceiver has been instructed to transmit an initial time delay may be introduced before the first data message is sent thereby allowing the RF stages to ac
5. 106 CTS has an ON condition logic 1 and circuit 109 DCD an OFF condition logic 0 ETIC MR1200 USER MANUAL 908709 02 Page 31 Operation Data transmission When there is data to be sent the terminal transmits it to the MR1200 On reception of the first data byte an attempt is made to access the radio channel see 4 4 If transmission is momentarily inhibited the MR1200 will delay data output for several seconds If radio channel access is refused see 84 4 the data sent by the terminal is lost Otherwise having gained access to the radio channel the MR1200 begins to send data Reception of data When not transmitting data the MR1200 is permanently listening out for radio channel activity If data is detected the modem informs the terminal using the 109 DCD line before passing it on The terminal cannot refuse communication with the modem Termination of radio communication When data transfer has been concluded no data awaiting transmission or being received the MR1200 returns to its rest state after a pre configured time delay tp rc parameter Communication may on the other hand be interrupted by the modem to avoid exceeding the pre configured maximum transmission time tp emi parameter if a value has been set Use of circuits 107 DSR and 106 CTS Circuit 107 DSR normally has an ON condition set during the period of radio data transfer and an OFF condition set when communication has ended However the configur
6. ESTE RD a ne ege ATE Ee peek E E 31 4 3 3 Marked automatic iode aiii e aset o eset ee be aid 32 434 Direct modes ot a yis euer Vere tese A eode ia 32 4 3 34 V25biSimodes a ede dns 33 4 4 RADIO CHANNEL ACCESS amp USE OF THE CCIR ZVEI TONE DIALLER cececene eene 36 GAL Introductionis did voee reges 36 ETIC MR1200 USER MANUAL 908709 02 Page3 Table of contents 44D IUUD A M 36 VAIS Radio telay controls uta qoe ge eee vis spe Ed 37 4 4 4 Usage in a V25bis call command sss eee 37 4 5 POWER SUPPLY SAVING SLEEP MODE ooooooocconoconoconconnconnonnnonononnnnnonn nennen erret nennen nnns 38 4 3 1 ODeFalion i e id tive etit tie e i tete eb e t ede eee etat 38 4 5 2 IMeepmodel i rte E Reate E eade eigo eundi 38 4 3 3 Transcelver WAKE UD a ha tee mo Dudum tdem eis 38 ADA ROWEF STALE UD C 39 4 5 5 Configuration mode wake up isses eene eene eene nan nn 39 ANG SPEECH USE terree e TN Pn E IRIS EE e NR 39 Page 4 ETIC MR1200 USER MANUAL 908709 02 Introduction 1 INTRODUCTION The MR1200 modem is designed for half duplex data communication over a radio frequency channel Connection is made to an external VHF or UHF transceiver The MR1200 exists in 2 versions 1200 b s version 2400 b s version EXTERNAL p gt TRANSCEIVER di MR
7. IC3 B may be changed to achieve the correct filter response This is a delicate operation requiring radio frequency measuring equipment and an SMD soldering kit see ETIC 2 6 1 2 The LFin connection The demodulated signal input stage consists of a passive band pass filter C12 R8 C14 an amplification stage IC3 C R4 P1 with gain adjustment using the multiturn potentiometer P1 The high input impedance means the LFin input stage will accept signals from the audio or external loudspeaker outputs of most T Rs Where the T R has a differential output the network R9 R10 R15 C9 C15 allows such an output to be connected In this case strap S1 must be moved Where possible it is preferable to use the differential mode configuration since it reduces noise ETIC MR1200 USER MANUAL 908709 02 Page 11 Installation 10 O 4BFin 11 r O 3BFin ic e gu ES F ol E E cat EL Mee The operation requires the copper track component side linking the S1 pins to be cut and a strap soldered in position as shown above P1 is factory set to give an RX level of 460 mV r m s when a signal of 1500 Hz 85 mV r m s is applied to the LFin input i T R CO i
8. Page 27 Configuration Parameter 053 tp ar Represents the minimum MR1200 wait time before changeover to transmission following radio channel data reception 1 20 ms Enter a low value 20 ms where applications function by a rapid exchange of data with brief request response intervals Enter a higher value 100 ms or more where data messages are long the control terminal s transmission data rate is less than 2400 bits s the flow of data is irregular Parameter 054 tp rc Defines the MR1200 wait time before terminating the current communication in the absence of either data being sent or received 2 100 ms Enter a low value 100 ms where applications function by a rapid exchange of data with brief request response intervals in automatic or direct control mode Enter a higher value 1 s or more in V25bis control mode 3 5 Leaving configuration mode Once modem configuration has been completed the operator activates the miniature push button switch a second time to return the unit to normal operation The TR and DP indicators go out and the modem serial interface is reconfigured with the speed and format parameters set by the operator Note Should the operator leave the MR1200 in configuration mode the unit will automatically revert to normal operation after 5 minutes Page 28 ETIC MR1200 USER MANUAL 908709 02 Operation 4 OPERATION 4 1 Principle Communication between MR1200 a
9. e e NL O nj sr RS232 2 6 1 3 The ALT connection The T R s change over to transmit mode ALTERNAT command either happens the instant circuit 105 RTS is set ON or when the ALT command generated by the data card is asserted A monostable triggered by 105 RTS prevents T R changeover occurring before data transmission has terminated MONOSTABLE monostable 100 ms gt l 10 ms min T1 65 lt ms max ALTERNAT Soft DATA out gt pes ca t y l ALTERNAT E R h Page 12 ETIC MR1200 USER MANUAL 908709 02 Installation 2 6 1 4 The DP connection optional In order to avoid collisions the data card uses the DP signal carrier detect or squelch inf to check the radio channel status before transmitting data Not all T Rs provide a carrier detect squelch output signal and in such cases the MR 1200 configuration need not take account of this input To generate its Channel occupied logic signal the modem compares the DP signal from the transceiver with a threshold voltage IC1 R7 R20 R22 P2 C6 The threshold level is adjusted with P2 Using straps S3 and S4 a positive logic level can be generated whatever the nature of the DP signal input S4 DP Logic ru MEA li L5V S3 esl DP Logic
10. the transmission chain bandwidth and any mismatching tolerable at 1200 b s will now produce signal alterations too severe for the modem to handle Furthermore in order to maintain the bit rate modulation frequency shifts at crossover take place every quarter cycle making the modem more sensitive to signal phase errors For transmission it is advisable to ensure that only one pre emphasis filter is used either by taking the modem output directly to the T R VCO or by strapping out the modem filter and using the filter on the transceiver microphone input different modulation index For reception it is imperative to have access to the demodulator output signal directly before the de emphasis stage thus avoiding the different LF stage filters in the receiver which alter the signal too much to enable data reception to be error free Connection block diagram TRANSCEIVER Page 14 ETIC MR1200 USER MANUAL 908709 02 Installation 2 7 Power saving feature set up The power saving feature not operative when the modem is in its normal awake state comes into operation when the unit is asleep Three jumpers on the data card need to be positioned to configure the different wake up modes There are two possible sleep modes SLEEP MODE 1 MR1200 asleep T R awake Wake up initiated by 108 2 DTR by radio CD or by the configuration mode push button being acti
11. 1200 Radio Modem Control terminal Measuring centre The general features of the MR1200 are Half duplex data transmission synchronous data transmission using FFSK modulation at 1200 b s or 2400 b s plus data protection using an error correction code RS232 or RS485 serial link to the Data Terminal Equipment with a choice of command modes including 3 wire automatic mode TxD RxD ground in RS232 mode 15 way sub D connector for connection to the external transceiver Radio channel access conflict management multiple equipment using the same radio channel Microphone loudspeaker set optional Possibility exists to selectively address a radio relay conforming to CCIR or ZVEI standards ETIC MR1200 USER MANUAL 908709 02 Page5 Introduction Minimal power consumption of 50 mA reduced to 300 uA using the power saving feature Durable and compact case housing the data handling interface card Completely configurable from an ASCII terminal using an elementary set of commands Page 6 ETIC MR1200 USER MANUAL 908709 02 2 INSTALLATION 2 1 Preamble Installation The MR1200 has an IP40 protection index For outdoor installation therefore it will be necessary to site the modem transceiver Data Terminal Equipment battery and any temperature regulating devices in a clean dry enclosure 2 2 External de
12. FIRT The terminal can itself cancel the current call command by setting 108 2 DTR to OFF modem returns to rest state When it finally gains access to the channel the MR1200 lets the terminal know by sending CNX Then 106 CTS is set ON to allow the terminal to send data Call reception When not transmitting the MR1200 permanently monitors radio channel activity If it detects incoming data when in the rest state it simultaneously sets ON 125 RI and 109 CD The terminal then has 6 seconds to accept the call by setting ON 108 2 DTR otherwise any incoming data will be lost If the terminal sets ON 108 2 DTR or if data communication is detected when a dialogue is in progress the MR1200 sets OFF 125 RI and sends an incoming call message to the terminal INC 106 CTS is then set ON to allow the terminal to communicate its data End of communication Communication ends with the timing as configured tp rc parameter once there is no more data to send or being received Alternatively the modem may interrupt communication to avoid exceeding the pre configured maximum transmission time fp emi parameter or the terminal may do so by setting OFF 108 2 DTR Whatever the case the MR1200 returns to either a rest or dialogue state depending on the condition of 108 2 DTR Use of circuits 107 DSR and 106 CTS Circuit 107 DSR is normally set ON during radio data transmission and set OFF when communication ends It can however be configured
13. MR1200 USER MANUAL 908709 02 Page29 Operation 4 2 2 Format and coding The MR1200 assembles the data sent by its control terminal into packets of varying size depending on the amount of data The packets are themselves sub divided into 64 bit frames of which 16 bits are used for the cyclic redundancy check code CRC when in base mode Before being transmitted each packet is preceded by a sequence of bits whose job is to synchronise the two modems SYNC Packet size variable SYNC frame 1 frame2 frame n 1 framen first frame 2 other frame Bm T T T T cket heading DATA CRC DATA CRC 16 bits 32 bits 16 bits 48 bits 16 bits 4 2 3 Operating conditions radio channel access At rest the MR1200 permanently checks for activity on the radio channel a transmit command may simply be refused if the channel is occupied absence of carrier for at least 0 1 seconds Half duplex timing When transmission begins the MR1200 systematically delays sending the first data in order to allow transceiver RF stages to develop full power tp alt parameter Data packet size Reducing or increasing data packet size will force the communicating modems to re synchronise the frequency depending on the application and the quality of the radio link f pag parameter Half duplex transmission The MR1200 control of T R switching half duplex is transparent to the terminal
14. R Resis 19 3 1 ENTERING CONFIGURATION MODE eese enne enne en nenn siet tene sn nete r entente sete nn sre r rennen nennen 19 3 2 CONFIGURATION COMMAND Sis ro eee ri EE Fe ERE aida as 19 3 3 QUICK CONFIGURATION i 5 ttes eit Ne RS o telis eee Re AeA Ne Shel 20 3 4 OPERATING PARAMETERS AND OPTIONS eese eene en eene nentes enter seen nn nn rra tense ennns 21 3 4 1 Configuring the terminal modem interface eese eene 21 3 4 2 Configuring the radio interface cnn 23 34S Operating PAV AM ELE a d eee reete A A A es eese vendo rie epe eu es uen 25 3 4 4 Power saving feature eese eee entente eterne ener entrent trente rennen nnns 26 3 4 5r Other parameter Sre 1 ei ee ere orte i ete s erp 27 3 5 LEAVING CONFIGURATION MODE csccsessecesseessceceeeeenceceseeeeneecsueeeeneeceeeeeaeecearesenseceseeseaaeceneeseneeeenees 28 4 OPERATION eer 29 4 Te PRINCIPLE o aoee a e IEEE 29 42 RADIO CHANNE Dran aiii 29 4 2 1 Data transmission method ccccccccccccccsssssssccccscsssssscsecececsesssessccscessesssasssecsecsesssssssesceseesssssaesees 29 4 2 2 Format ANA coding sd iaa 30 42 3 Operating conditions dal o deer ee dope tet tn de pay ede deepest ide e nente petet 30 4 3 MODEM CONTROLDMODES c biete prp OP ee petet bed brc rv t i pr b 31 4 3 1 The terminal modem interface esee eee entente trennen nnne 3l 2 3 2 AUTOMATICO 2 io stes s Cate aaa os a
15. The use of buffers enables terminal modem dialogue to remain duplex throughout The modem will switch from transmission to reception according to a configurable timing parameter tp ae parameter when there is no more data to be sent The MR1200 stays in the receive state while data is incoming reverting to transmission at the end of a second configurable time delay if the terminal has new data tp ar parameter tp ae ip ar T T T d S packet 1 Sync packet 2 Sync packet 3 4 y y ip Bync packet 1 Receive state Received data restoration and error treatment base mode The CRC of each frame received is tested and frames with CRC errors are either eliminated or signalled using a configurable character error parameter The MR1200 extracts the data from each error free frame placing the bytes end to end The data is re transmitted to the terminal either as it arrives or as a block of data once the last frame has been received and restored block mode option bloc parameter Page 30 ETIC MR1200 USER MANUAL 908709 02 Operation Duration of data emission The MR1200 will continue transmitting data for a limited period of between 1 and 255 seconds tp emi parameter after which the modem will pause for a period also of between 1 and 255 seconds tp rec parameter to allow other modems to gain access to the radio channel If transmission time limits have been set long messages shou
16. anently listening out for radio channel activity If data is detected the modem informs the terminal by setting ON the 109 DCD line before passing the data on The terminal cannot refuse communication with the modem Line 106 CTS is also set ON enabling the terminal to reply with its data Termination of radio communication The MR1200 returns to its rest state after the pre configured time delay once 105 RTS is set OFF AND data transfer has been concluded parameter tp rc Communication may on the other hand be interrupted by the modem to avoid exceeding the pre configured maximum transmission time tp emi parameter if a value has been set Use of circuits 107 DSR and 106 CTS Circuit 107 DSR is normally set ON during radio data transmission and set OFF when communication ends It can however be configured to be ON permanently ges dsr parameter Once radio transmission has begun 107 CTS remains ON and is only set OFF to signal transmission data buffer overflow The signal can be used to control data flow from the terminal 4 3 5 V25bis mode The V25bis control mode makes a more extensive use of the serial interface only 105 RTS is unused giving the terminal total control over the modem through a set of commands and responses defined by the V25bis standard Where a number of radio modems are networked individually addressed data messages can also be sent out Each modem is allocated a number between 001 and 255 consti
17. ata to a destination modem when automatic or direct control mode has been set from 0 to 255 BCD 0 no address If either the ad mod parameter is null or V25bis control mode is being used the value of the ad dest parameter is ignored Parameter 033 phonie An optional microphone loudspeaker set can be connected to the MR1200 for combined data and speech transmission working see chapter 2 In such a case the phonie option must be enabled Otherwise it is best to inhibit it ETIC MR1200 USER MANUAL 908709 02 Page 25 Configuration phonie speech transmission 0 Inhibitd Enabled Parameter 034 f paq f paq sets the maximum data packet size the MR1200 will transmit The value set determines the frequency of the re synchronisation sequences exchanged between the communicating modems see chapter 4 0 I2byes 8 192 bytes 9 216 bytes Select a small packet size 48 bytes or less if transmission conditions are only mediocre Select a larger size 144 bytes or more if the radio link is of good quality and the data rate needs to be high Parameter 035 f mem Alters the MR1200 s transmit data buffer size from 32 bytes to 2 Kbytes depending on the application buffer capacity 0 32bytes 1 64byes 2 I28byes 1 2 1024 bytes 6 2048 bytes 3 4 4 Power saving feature Parameter 043 att ina Page 26 ETIC MR1200 USER MANUAL 908709 02
18. ation option exists to set this circuit permanently ON ges dsr parameter Circuit 106 CTS is ON most of the time being set OFF only when the data transmission buffer overflows The signal may be used to control data flow from the terminal 4 3 3 Marked automatic mode Marked automatic mode is simply a variant of automatic mode the only difference being with transmission control in this mode transmission begins on detection of a particular pre defined character used to end all files to be transmitted The ASCII character code is configurable mark parameter 4 3 4 Direct mode In direct mode transmission is controlled using the RTS signal Rest The terminal holds OFF circuit 105 RTS logic 0 Circuits 106 CTS and 109 DCD are both OFF Data transmission When there is data to be sent the terminal begins by setting ON the 105 RTS line The modem then attempts to gain access to the radio channel see 4 4 If transmission is momentarily inhibited the MR1200 will delay outputting data for several seconds Radio channel access may however be refused see 4 4 in this case 106 CTS remains OFF but the terminal can maintain 105 RTS ON in readiness for another attempt Having finally obtained access to the radio channel the MR1200 sets ON line 106 CTS authorising the terminal to send its data Page 32 ETIC MR1200 USER MANUAL 908709 02 Operation Reception of data When not transmitting data the MR1200 is perm
19. by the st num parameter value 4 4 4 Usage in a V25bis call command In V25bis mode the terminal can place a particular call sequence in the call command CRNaaa ss s where aaa is a radio modem network address and ss s is the call sequence to use This sequence is then only used by the MR1200 at the beginning of transmission Once communication has been established the call sequence is that programmed in the seq num parameter Equally the terminal can transmit a call sequence for the MR1200 to execute without there being any subsequent data CCIR or ZVEI pager calling The syntax is then CRN Ss s where ss s is the call sequence to execute ETIC MR1200 USER MANUAL 908709 02 Page 37 Operation 4 5 Power supply saving sleep mode 4 5 1 Operation The MR1200 is equipped with a power saving system that deactivates particular modem functions during periods of complete inactivity in order to reduce power consumption to a minimum 3001A The functions are reactivated when one of the following events occurs terminal sends a command circuit 108 2 DTR set ON radio channel activity carrier detected modem first powered or re powered after a loss of supply operation of the configuration button Note the sleep mode chosen is set by straps on the circuit board 4 5 2 Sleep mode When inactive the MR1200 drops into sleep mode after a configurable time delay of between 1 second and 60 minutes at
20. cation To read a modem s configuration quickly use the RLP P1 and RLP P2 commands to provide a two page listing of the settings Once configured it is advisable to write down the modem settings in the MODEM CONFIGURATION table provided in the appendix 3 4 Operating parameters and options The following paragraphs describe the MR1200 configuration parameters in detail The default values for MR1200 parameters and options have a next to them These are the values assigned when the modem is first switched on or when the RES1 command is sent 3 4 1 Configuring the terminal modem interface Parameters 010 f v24 and 011 v v24 ETIC MR1200 USER MANUAL 908709 02 Page 21 Configuration These set the speed and data format of the terminal modem serial link for normal operation i e other than configuration mode 0 7El 7 bits even parity 1 stop 150 b s 1 701 7 bits even parity 1 stop 300 b s 7 2 7 bits no parity 2 stops 2 600b s 7E2 7 bits even parity 2 stops bj 5 8 1 8 bits no parity 1 stop 4 2400bs 4800 b s 8El 8 bits even parity 1 stop 6 9600b s Nn 8 bits even parity 1 stop 8 2 8 bits no parity 2 stops Parameter 012 mod_ter Defines the MR1200 control mode used for normal operation from the 4 possible modes 0 marked automatic simple automatic V25bis Either of the automatic modes is adequate in most instances
21. d ICS in order to directly drive a 4 Q loudspeaker Warning the LS output signal is referenced to 5V The loudspeaker must therefore be connected between the HP and V 5V outputs available on the female 9 way sub D connector For a signal of 1500 Hz 85 mV r m s applied to the LF input transceiver interface the power delivered to a 4 Q LS is approximately 25 mW If the set used incorporates amplification i e has a high impedance input better audio quality can be obtained by taking the LS signal directly from the output of IC3 D behind C8 and if necessary increasing the level by modifying the values of R3 and R17 consult ETIC The pinout of the female 9 way sub D connector is as shown 5 1 000090 ecce 1 5 5 V cut when the MR1200 is in sleep mode 2 LS output 3 microphone input 4 transmit control o p PTT connected to pin 5 for transmit 6 3 ground ih D RS485 8 RS485 Adaptation to adapt impedance of the RS485 serial link by connecting pin 7 to pin 8 S D RS485 The interface was designed for a particular microphone LS set for sale under reference MIC 02 Using another kind of set may necessitate modifications to some of the discreet components on the card 2 8 2 PTT connection push to talk The MR 1200 needs a TTL logic signal to control the T R changeover to transmission OV wait reception 5V transmission Page 16 ETIC MR1200 USER MANUAL 908709 02 Ins
22. e to cancel this echo if the terminal echoes its keyboard input locally 3 3 Quick configuration This paragraph describes the minimum configuration necessary to get the modem up and running quickly When completed the MR1200 will function in automatic mode communication using 4 serial interface circuits 103 TD 104 RD 106 CTS and 102 SG The power saving feature will not be operative Connect an ASCII terminal type VT100 or a PC emulating VT100 to the MR1200 using a 4 wire cable carrying circuits 103 TD 104 RD 106 CTS and 102 SG of the RS232 serial interface Apply power to both terminal and modem Configure the terminal s communication port for 1200 bits s 7E1 no handshaking Operate the miniature push button CONFIGURATION switch on the MR1200 front panel All modem indicators will then come on and C gt should appear on the terminal screen Enter the command RES1 followed by Cr The indicators should go out Operate the CONFIGURATION push button switch once more to turn the indicator lamps on again and bring back the C gt cursor Page 20 ETIC MR1200 USER MANUAL 908709 02 Configuration Enter the command PRP010 x followed by Cr where x is a number between 0 and 8 coding the data format that the MR 1200 will use for communication with the terminal x 0 7El 7 bits even parity stop x 5 8 1 8 bits no parity 1 stop x 701 7 bits even parity 1 stop x 6 8El 8 b
23. ed yes ye Co 12511 Received call indicator V2Sbis mode optional optional optional Remarks The command data terminal can be any type as long as its serial interface can function with the following speeds and transmission formats Page 8 ETIC MR1200 USER MANUAL 908709 02 Installation speed 150 300 600 1200 2400 4800 or 9600 bits s format 7E1 701 7 2 7E2 702 8 1 8E1 801 or 8 2 In practice RS232 cables should be no longer than 15 metres If the installation is exposed to electrical or radio disturbance reduce cable lengths to a minimum 2 4 Choice of radio channel data transmission rate As standard the modem uses a 1200 baud radio channel data rate It can also be factory configured to work at 2400 baud 2 5 Power supply connection The MR1200 needs a d c power supply voltage of between 10 6 V et 15 8 V When used on an isolated site a 12V lead battery is an ideal solution The MR1200 is fitted with a circular male power supply connector whose pinout is as shown Ja N 4 2s 3 J 0 A 1 12 V 2 ground 3 not connected Remarks The MR1200 does not possess an ON OFF switch The MR1200 works from a single source of power Where two power sources are used battery solar panels for example switching between them must be done externally 2 6 Connecting to the transceiver The MR1200 has been designed to be connected to different types of VHF or UHF transceiv
24. ers T R Connecting to a T R does however require level adjustments to be carried out and sometimes changes to be made to the circuit board 2 6 1 Description of the LF interface signals For the radio link the MR1200 uses a 15 way sub D connector whose pinout is shown below ETIC MR1200 USER MANUAL 908709 02 Page 9 Installation 8 1 00000000 N 15 9 9 LFout LF transmit output 11 LFin main LF receive input 10 LFin secondary LF receive input for differential input mode 162 3 ALT half duplex control 12 DP radio carrier detect or squelch inf optional 6 Vreg Output for T R power supply relay control 5 GND T R signal ground 8 GND T R signal ground 14 12 V reserved for modem card power supply from the transceiver 15 OV reserved for modem card power supply from the transceiver 7 reserved 13 reserved 4 reserved 2 6 1 1 The LFout connection The output stage levels are calculated to match the VCO input of a classic analogue phase modulated transmitter The circuit diagram below shows an amplification stage IC3 A R25 P3 with gain adjustment using the multiturn potentiometer P3 a signal pre emphasis stage IC3 B C17 C15 C3 C4 R19 R11 R12 providing the correct levels at the VCO input to obtain the frequency excursions recommended by the ST PAA DIR 1382 standard a mm y VRO modulat
25. having been designed to allow the modem to operate transparently using only circuits 103 TD and 104 RD and 106 CTS for handshaking if required In direct mode the terminal uses an extra circuit 105 RTS to control access to the radio channel before sending data The V25bis control mode uses all the serial interface signals except 105 RTS to give the terminal total control of the modem through a set of commands and responses corresponding to the V25bis standard Where a number of radio modems are networked individually addressed data messages can also be sent Parameter 013 echo Enables or cancels the echoing of configuration commands PRP RLP on the terminal screen If the terminal already has local keyboard echo it is advisable to set the value of this parameter to 0 no yes Parameter 014 mark Page 22 ETIC MR1200 USER MANUAL 908709 02 Configuration Defines the ASCII control code for the character used to control data transmission in marked automatic mode see chapter 4 from 0 to 255 BCD 013 A value of 013 is used to start transmission of a line of characters on reception of the Cr Carriage Return control character Parameter 015 error When not null the error parameter determines the code of the ASCII character sent to the terminal signalling reception over the radio channel of an invalid frame error from 0 to 255 BCD 000 000 used to cancel the signalling of invalid frames
26. hieve nominal power from 0 to 255 30 300 ms Parameter 022 ges dp Determines whether or not the carrier detect signal is used The DP signal is derived from the receiver RF stages and indicates the current status of the radio channel DP implemented no yes In the case of applications comprising several modems likely to transmit simultaneously multi master network random access network ges dp should be implemented in order to limit radio channel collisions Where exchange of data is controlled by a master station master slaves network this option may be deselected to reduce modem turn around delay to a minimum Parameter 023 st num Allows selection of the MR1200 CCIR ZVEI tone encoder operating mode CCIR CCIR short ZVEI 1 ZVEI 2 Parameter 024 seq num Defines the tones to be emitted and or the protocol used by the MR1200 each time it goes into transmit mode Tone codes 0 to 9 A to E Chain of 10 null chain Control codes 2 gt W characters max By default the seg num parameter is empty the MR1200 simply testing the availability of the channel before transmitting any data In order to turn on and control the carrier of a CCIR or ZVEI relay the seq num parameter must be programmed with a chain of characters having the form nn nz where nn n is the relay s selective call number For more details on character chain coding for the seq num parameter refer
27. ing signal radio frequency excursion fo 1800 Hz Af 1 57 kHz 0 2 kHz 0 32 kHz f 1200 Hz Af 1 04 kHz 0 13 kHz 0 21 kHz The pre emphasis stage is in fact a 2nd order high pass filter defining the following relationship Page 10 ETIC MR1200 USER MANUAL 908709 02 Installation Afo Afi 154 0 12 kHz If the transmitter used has an input marked external mic it is quite likely that pre emphasis is already provided at the input stage In this case it is possible to bypass the modem pre emphasis stage by moving jumper S5 as shown below SET RS282 Potentiometer P3 then enables the level of the T R input signal to be set so that the recommended frequency excursions Af and Af can be obtained P3 is factory set for a signal of 175 mV r m s at 1200 Hz and 265 mV r m s at 1800 Hz Depending on the type of microphone specified for the equipment the T R manufacturer may have used filters having responses that could upset data transmission In this case a complete transmitter frequency response spectrum will be required in order to determine the characteristics of any compensating filter needed to obtain the recommended radio channel frequency excursions The discreet components around
28. isation carried out default parameters Remarks The symbols p or a represent ASCII numbers The value vv v ofa parameter is given in the form of an ASCII chain coding depends on the parameter All terminal commands must comprise ASCII characters and end with a control code Cr Carriage Return or with the Cr Lf Carriage Return Line Feed combination The modem terminates its replies with Cr Lf A sequence of the form ss s transmitted as part of a CRN command tells the modem which particular radio channel access protocol to use as well as to activate CCIR ZVEI tone encoder the CCIR or ZVEI standard is selected with st num parameter Refer to 4 4 for the use of this command Page 34 ETIC MR1200 USER MANUAL 908709 02 Operation Call command When the terminal wishes to send data it sends the modem a call command having the following syntax CRNaaa Cr or CRNaaa ss s Cr where aaa is the network address of the modem receiving the data and ss s is an optional CCIR ZVEI call sequence If the command sent is incorrect the reply is INV Otherwise the MR1200 sets ON 106 CTS and attempts to access the radio channel see 4 4 If transmission is momentarily inhibited the MR1200 sends a delayed call response to the terminal DLCxx where xx is the wait time in seconds If access to the channel is refused the MR1200 replies with the appropriate error message see 4 4 CFIAB or C
29. itches the T R into transmission Holding the button down and using the microphone the operator s speech will be transmitted any request from the terminal to send data being ignored Releasing the button switches the T R back to receive mode enabling the operator to listen to his correspondent and data communication to be re established ETIC MR1200 USER MANUAL 908709 02 Page 39
30. its even parity 1 stop x 2 7 2 7 bits no parity 2 stops x 7 801 8 bits even parity 1 stop x 3 7E2 7 bits even parity 2 stops x 8 8 2 8 bits no parity 2 stops x 4 702 7 bits even parity 2 stops Enter the command PRP011 y followed by Cr where y is a number between 0 and 6 coding the data rate the MR 1200 will use for communication with the terminal y 0 150b s y 3 1200b sy 6 9600 b s y 1 300b s y 4 2400 b s y 2 600b s y 5 4800 b s e If the MR1200 is to be used to transmit MODBUS JBUS frames enter the command PRP030 1 followed by Cr Now use the RLP53 command followed by Cr to check that when receiving data the wait time is sufficiently long so as to not strip off these frames and thus inhibit block mode LSP53 5 minimum Operating the CONFIGURATION push button one last time will turn off the indicators and disconnect the terminal Connect the modem to one of the DTEs that will be using radio communication The MR1200 will work with a 4 wire cable carrying the RS232 serial interface circuits 103 TD 104 RD and 02 SG A wire for the 106 CTS signal is optional the modem uses this circuit for handshaking Check which DTE serial interface loops are necessary for it to function correctly most PCs for example require a loop between the 107 DSR and 08 DTR lines plus the 106 CTS circuit to be wired Prepare and install the other radio modems in the same way before running the appli
31. ld be segmented and sent by the terminal in several batches otherwise data may be lost modem memory capacity The size of the MR1200 s transmit buffer can be increased from 32 bytes up to 2 Kbytes depending on the application 4 3 Modem control modes 4 3 The terminal modem interface The MR1200 dialogues with its control terminal across a standard RS232 serial interface The following table describes the circuits comprising the serial interface their function their use according to the operating mode chosen automatic direct V25bis 102 SG 5 Sigal gound yes yes yes 104 RD 2 modem gt terminal Received data yes yes yes 105 RTS 7 terminal gt modem Readytosend ES PE 106 CTS 8 modem gt terminal Cleartosend advised yes yes 107 DSR 6 modem gt terminal Datasetready optional advised yes ER optional optional optional 125 RI 9 modem gt terminal Ring indicator optional optional optional Its 4 control modes enable the MR1200 to be used with a large range of terminals making it easily adaptable to particular user applications 4 3 2 Automatic mode In this mode radio modem operation is transparent to the terminal with only the 3 circuits 103 TD 104 RD and 102 SG being used If necessary circuit 106 CTS may be implemented for handshaking requirements Data transmission begins on detection of a specific character Rest Circuit
32. me on and the following message will appear on the terminal screen gt l Serial connector for terminal link male 9 way sub D 2 Miniature push button switch selects configuration mode 3 2 Configuration commands Operating parameters and options are programmed into and read from the MR1200 s E2PROM memory using commands and responses as defined in the CCITT V25bis standard ETIC MR1200 USER MANUAL 908709 02 Pagel9 Configuration Terminal commands Modem responses HHH lt erroneous command gt INV Command invalid PRPppp vv v Programme parameter ppp VAL Command accepted with value vv v Read parameter ppp LSPppp vv v Indicates value vv v of parameter ppp Read page n of the LSPpppl vv v to configuration n 1 or 2 LSPpppn vv v Indicates value vvv v for parameter pppl1 to pppn Reinitialise terminal modem Reinitialisation carried out dialogue Reinitialise modem using the Reinitialisation carried out default parameters Remarks symbols shown by p represent ASCII numbers the value vv v of a parameter is given in the form of an ASCII chain coding depends on the parameter all terminal commands must be composed of ASCII characters and terminated by the control code Cr Carriage Return or by the Cr Lf Carriage Return Line Feed combination The MR1200 echoes all the commands it receives on the terminal screen It is always possibl
33. nd control terminal takes place over the RS232 serial link The modem then obtains access to the radio channel and finally sends the data to be transmitted Call control 4 control modes enable the terminal to control the modem The MR1200 then checks the status of the radio channel turns on a relay if appropriate and finally transmits the data Data Communication Data transmission over the radio channel is half duplex Communication between the modem and terminal is duplex 4 2 Radio channel 4 2 1 Data transmission method The MR1200 radio modem adheres strictly to the specifications laid down in the French standard ST PAA DIR 1382 Radio channel data transmission is synchronous and uses a data rate of 1200 or 2400 b s The modulation employed is of an indirect type an FFSK modulated audio frequency sub carrier phase modulates a radio frequency carrier Normal transmission is in base mode data to be transmitted 1s formatted into frames protected by a cyclic redundancy check code CRC giving a useful radio channel data rate of 900 b s Another transmission mode without CRC called simple mode is also available but should not be employed unless the radio link is of good quality communicating stations relatively close and where a useful radio channel data rate greater than 900 b s 1s essential The data is transmitted without any extra coding and errors are no longer filtered out on reception of data ETIC
34. on disable transmission receive short pause 100 ms long pause 2 s Examples T wait for channel to become free 6s max if channel free transmit if not report CFIAB failure Page 36 ETIC MR1200 USER MANUAL 908709 02 Operation 1122W33 wait for channel to become free 6s max if not report CFIAB failure transmit tone sequence 122 then pause for 2s transmit tone sequence 33 then return to rest state gt test for relay carrier 6s max 1f carrier present transmit if not report CFIRT failure 21A22 gt test for relay carrier if absence of carrier detected transmit 1A22 test for relay carrier if relay carrier present transmission if not report CFIRT failure if not transmit immediately 4 4 3 Radio relay control At each switch over to transmission during radio communication the MR1200 CCIR ZVEI tone dialling system can be activated using a call command For this the seq num parameter simply needs to be programmed with the appropriate call sequence By default this parameter is null the MR1200 using its carrier detect facility to check channel availability each time before it transmits similar to a gt sequence To activate and control a CCIR or ZVEI relay carrier the seq num parameter must be programmed with a sequence respecting the following syntax nn n gt where nn n is the selective call number of the relay CCIR or ZVEI mode is selected
35. scription The MR1200 modem is housed in a metal box Dimensions 180 x 130 x 45 Lx W x H Overall weight 550 g Impact and penetration IP40 Fixing centres 120 mm lt Up UA LA E VAM A p o We Nw adi Ml HEAT i 3 J l n Cre 910159 31153 171 Ens ETIC MR1200 USER MANUAL 908709 02 Page7 Installation 1 Serial connector to data terminal male 9 way sub D 2 Miniature push button switch to enter configuration mode 3 RS485 serial link or Microphone loudspeaker connector optional reference MIC 02 Power indicator Radio transmission TR and reception DP indicators External transceiver connector female 15 way sub D Power connector 10 to 16 Volts 2 3 Connecting to the terminal The MR1200 dialogues with its command terminal over an RS232 12V 12V serial link The connector used is a male 9 way sub D whose pinout is as shown 1 5 00000 oe o The different circuits carried on the interface are shown in the following table Pin Circuit Function Usage according to control mode automatic direct V25bis O1 109 us Detection of modulated carrier r a Ea 2 104 RxD Data reception 3 109 TD e feom Wake V2sh done opon option yes 5 102 SG Signal ground es e Lets Rao sommer teni s yes 7 105 RTS Send command in directmode 3 10518 Clear to send Glow contra advis
36. t ina parameter If one of the above events occurs before the time out the modem remains awake and the countdown is stopped Note The att ina parameter can be forced to 0 in this case the power saving feature in inoperative 4 5 3 Transceiver wake up The transceiver s power supply can be relay controlled using the MR1200 V ggg output When the MR1200 drops into sleep mode the Vreg signal disconnects the transceiver power supply RX MR1200 IGND Transceiver Vreg 7 V Page 38 ETIC MR1200 USER MANUAL 908709 02 Operation 4 5 4 Power up state When the MR1200 is first powered or repowered after a loss of supply it remains awake until after the first radio communication has taken place 4 5 5 Configuration mode wake up Operating the configuration push button switch will cause the modem to wake up so that its different operating parameters can be programmed On leaving configuration mode the modem remains awake until after the first radio communication has taken place 4 6 Speech use Where applications use the radio channel for both speech and data communication the MR1200 can be equipped with a microphone loudspeaker set In this case the phonie option must be selected When the operator wishes to speak he pushes the transmit receive button on the set The MR1200 then suspends all current data communication and sw
37. tallation The PTT signal is derived simply by closing a pair of contacts operated by the changeover button Push to talk button 5V EE Th gt 4 L O PTT Boar 2 8 3 MICROPHONE connection The external microphone signal is amplified and filtered low pass filter IC3 A C18 R21 P3 4 C16 If necessary the signal level can altered by modifying resistor R21 consult ETIC 2 9 T R power supply The transceiver connected to the MR1200 should have an external power source For sleep mode operation the Vreg output can then be used to control a T R power supply relay MR1200 OND TRANSCEIVER Vreg ETIC MR1200 USER MANUAL 908709 02 Page 17 Configuration 3 CONFIGURATION 3 1 Entering configuration mode Programming or listing the complete set of MR1200 operating parameters may be carried out using a data terminal connected via the serial interface The terminal must be set up with the following communication parameters transmission speed 1200 bits s transmission data format 7E1 7 bits even parity 1 stop Once the terminal has been installed and the equipment powered the operator pushes the CONFIGURATION miniature push button found on the modem front panel At this point any radio communication in progress will be terminated indicators TR and DP will co
38. to be ON permanently ges dsr parameter Once radio transmission has begun 106 CTS remains ON and is only set OFF to signal transmission data buffer overflow It can be used to control the flow of data from the terminal ETIC MR1200 USER MANUAL 908709 02 Page 35 Operation 4 4 Radio channel access amp use of the CCIR ZVEI tone dialler 4 4 1 Introduction Two elements comprise the MR1200 tone dialling system the radio carrier detection circuitry and a tone encoder conforming to CCIR or ZVEI standards This system can be programmed to operate and control carrier activation of a relay conforming to CCIR or ZVEI standards call paging devices conforming to CCIR or ZVEI standards or simply test radio channel availability before transmission in order to avoid collisions its 4 4 2 Programming The choice between CCIR or ZVEI mode is programmable st num parameter The tones to transmit and or the radio channel access code are defined in a call sequence comprising a chain of up to 10 max ASCII characters chosen from the following symbols A to E CCIR or ZVEI mode test for channel availability no radio carrier wait time 6s max H test relay carrier activation follows sequence sent if carrier present radio carrier present wait time 6s max deactivate half duplex then test for presence of relay carrier Follows sequence sent if carrier absent see examples below enable transmissi
39. to chapter 4 84 4 Page 24 ETIC MR1200 USER MANUAL 908709 02 Configuration 3 4 3 Operating parameter Parameter 030 bloc For normal operation the block option is deselected data being passed on to the terminal as soon as it has been extracted from the frames received over the radio link In block mode data is stored until a complete message has been received whereupon a block of data is passed on in an uninterrupted stream bloc block mode yes Normal mode is the quicker option for modem to terminal data handling However subject to testing block mode may be selected when the terminal needs to have data presented in a continuous stream as with MODBUS JBUS data frames for example Block mode is only possible when the modem is configured for 2400 b s radio channel working Parameter 031 ad mod Each MR1200 modem on a transmission network can individually receive data by being allocated a unique address notably when the V25bis control mode is used see chapter 4 The ad mod parameter represents the individual modem s address from 0 to 255 BCD 0 no address If 0 is entered for this parameter the MR1200 will not use an address when it transmits data To address data to stations within a transmission network enter different non zero addresses for each communicating station Parameter 032 ad dest Where a modem has been allocated an address ad mod parameter the parameter ad dest may be used to address d
40. tuting its network address ad mod parameter Rest The terminal holds the 108 2 DTR line OFF logic 0 Circuits 106 CTS and 109 DCD are also OFF Dialogue The terminal opens communication with the MR1200 by setting ON 108 2 DTR The modem replies by setting ON circuit 106 CTS Under these conditions the MR1200 waits for commands and gives responses as per the V25bis standard CCITT ETIC MR1200 USER MANUAL 908709 02 Page 33 Operation Terminal commands Modem responses lt Erroneous command gt PRPppp vv v Programme parameter ppp VAL with value vv v RLPppp Read parameter ppp LSPppp vv v CRNaaa Transmit command aaa address of modem receiving the data CRNaaa ss s Transmit command with a particular CCIR ZVEI call sequence aaa address of modem receiving the data ss s call sequence CRN Ss s CCIR ZVEI call sequence transmit command Ss s call sequence Modem at rest gt Command invalid Command accepted Indicates the value vv v of parameter ppp Call delayed xx seconds Radio channel occupied Start of radio transmission Call delayed xx seconds Radio channel occupied No response from relay Access to channel obtained Start of radio transmission Transmission of sequence terminated Detection of a radio transmission addressed to the modem RESO Reinitialise terminal modem Reinitialisation carried out dialogue RESI Reinitialise modem with V Reinitial
41. vated SLEEP MODE 2 MR1200 asleep T R not powered In this case power for the T R is supplied through a relay controlled by the MR1200 Relay operation 1s described in chapter 4 5 3 Wake up initiated by 108 DTR or by the configuration mode push button being activated Configuring the straps for SLEEP MODE 1 Cut the copper track linking the pins of S12 component side and solder a strap in position as indicated on the drawing below If it is desired to confirm modem wake up through the radio CD solder a strap on S2 as indicated on the drawing below Configuring the straps for SLEEP MODE 2 Cut the copper tracks linking the pins of S12 and of S11 component side and solder a strap in position as indicated on the drawing below s2 al z Cll n Z S 12 8 I o O b S D a o n La S E e fs 11 O 7 gt 2 E Tu aL 3 ia m J i ETIC MR1200 USER MANUAL 908709 02 Page 15 Installation 2 8 Connecting the optional microphone loudspeaker set A set compatible with the MR1200 is available having reference MIC 02 2 8 1 Description of the microphone loudspeaker interface The demodulated signal is amplified circuit around IC3 D an
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