Model 8277 Table of Contents
Contents
1. back to form a simple high speed full duplex optical link In optical ring operation two or more 8277s are cascaded in a ring A ring consists of one master modem and two or more slaves see Figure 2 The slaves pass received optical data and transmit data from their electrical interface to their optical transmitters The master does not pass received optical data Master slave modes are switch selectable Master mode is selected for both modems in an optical point to point configuration Single Fiber Model 8277 inMaster Mode All other 8277sin Slave Mode Figure 2 Optical Ring Note In RS 485 two wire mode when configuring the Model 8277 in an optical ring the master cannot be enabled by the TD signal The Model 8277 optical interface can form a ring of up to ten units This allows for a maximum optical system loss budget of 120 dB In order to extend the optical distance between any two Model 8277s the units are inserted in the optical path to act as line extenders Slave mode should be selected for optical line extenders see Figure 3 eae Model 8277s in Slave Mode Figure 3 Extending Optical Distance Note The Model 8277 transmits infrared light which is not visible to the eye Page 4 of 10 1 3 Electrical Interface The Model 8277 s electrical interface is switch selectable to RS 232 or RS 422 RS 485 voltage levels When the RS 232 interface is selected communications to the electrical interface2. cases where NO TROUBLE is found a reduced charge will be billed to cover handling testing and packaging Whether in or out of warranty a Return Material Authorization RMA number is necessary and can be obtained by calling 631 423 3232 or 1 800 835 3298 by faxing 631 385 8184 7060 or by e mailing us at support telebyteusa com You can also visit us on the web at www telebyteusa com rma htm Reference the RMA number on the outside container Document No 0315 0292 Rev F Distributed by CONNECTIVITY L com PRODUCTS 45 Beechwood Drive North Andover MA 01845 www L com com E mail sales L com com Fax 978 689 9484 Toll Free 800 343 1455
3. conditions is met a With the DCE DTE switch in the DCE position Pin 3 TD will turn on the LED or b With the switch in the DTE position Pin 2 RD will turn on the LED For RS 4XX with the DCE DTE switch in the DCE position a voltage more positive on Pin 6 TD than on Pin 2 TD turns this LED on With the switch in the DTE position the line monitors are Pin 1 RD and Pin 3 RD Note In RS 485 two wire mode when configuring the Model 8277 in an optical ring the master cannot be enabled by the TD signal FTD Fiber Transmit Data This LED turns on when light is transmitted from the optical transmitter In the slave mode this is the logical OR of light coming into the optical receiver and a high on the data coming from the user at the electrical interface LTD In the master mode this is the same as LTD FRD Fiber Receive Data This LED is used to monitor the data going into the optical receiver The LED turns on when there is light on the fiber connected to the receiver COL Collision This LED is used to monitor collisions on the fiber This indicates a system problem The COL LED turns on when the Model 8277 is being used in an optical ring and more than one slave is trying to transmit to the master unit In the master mode this LED is disabled Page 10 of 10 5 0 Help If you require assistance please call Telebyte Customer Service at 631 423 3232 fax us at 631 385 8184 or e mail us at support teleb
4. Page 1 of 10 O Telebyte Your world wide source for fiber and copper connectivity w Model 8277 Multimode Fiber Optic Modem Reference Manual 0315 0292 Rev F Printed 11 07 01 Table of Contents 1 0 Equipment Description 1 1 Introduction 1 2 Optical Interface 1 3 Electrical Interface 1 4 Flow Control 2 0 Specifications 2 1 Optical Interface 2 2 Electrical Interface 2 3 General Specifications 3 0 Equipment Operation 3 1 Switch Options 3 2 Connections 4 0 Indicators 5 0 Help Page 2 of 10 1 0 Equipment Description 1 1 Introduction The Model 8277 Multi mode Fiber Optic Modem is an asynchronous product The optical interface can operate in either point to point or ring configurations and employs two ST type connections The unit operates on fiber optic cables with core diameters from 50 to 100 microns The electrical interface operates in either point to point or multi drop configurations When configured as RS 232 or RS 422 the unit will operate point to point With the RS 485 interface selected equipment can be multi drop connected onto low cost twisted pair wire see Figure 1 The versatility of the two interfaces of the Model 8277 allows for an extremely flexible system design RS 485 Network on 1 twisted pair Figure 1 RS 485 Multi drop Configuration Page 3 of 10 1 2 Optical Interface In an optical point to point configuration two Model 8277s are connected back to
5. are full duplex point to point With this interface data can be transmitted onto the optical fiber for a point to point optical link or for an optical ring Switch selection enables data to flow from the electrical interface to the optical transmitter or can be controlled by a high on RTS On the electrical interface a high on the Data In pin causes light to be emitted Full duplex four wire or half duplex four or two wire mode may be selected when the RS 422 RS 485 interface is selected The RS 422 RS 485 interface of the Model 8277 can operate in a multi dropped or point to point environment If RS 422 mode is selected the electrical interface is only point to point If the customer s equipment has an RS 485 interface it can be multi dropped directly onto the Model 8277 s interface by selecting the four wire or two wire RS 485 mode If the customer s equipment has an RS 232 interface the equipment can be converted to a multi drop RS 485 interface by a Telebyte Model 285 Up to 31 units of the Model 285 can be multi dropped onto the same electrical interface of the Model 8277 1 4 Flow Control Operation in the RS 485 multi drop or the ring environment requires that all devices connected to the line have some level of intelligence in order to establish an orderly flow of data When RS 485 half duplex mode is selected the Model 8277 controls the Receive Data line on the electrical interface When data is not received no light on fiber by t
6. he optical receiver for ten microseconds the output of the Receive Data electrical transmitter is tri stated In RS 485 mode this enables many transceivers to communicate on the same twisted pair When the RS 485 two wire mode is selected half duplex data is transmitted and received on the same twisted pair Note In RS 485 two wire mode when configuring the Model 8277 in an optical ring the master cannot be enabled by the TD signal Page 5 of 10 2 0 Specifications 2 1 Optical Interface Optical connectors ST trademark AT amp T Power Out gt 15 dBuW 32 microWatts into 62 5 125 um core clad fiber Power Budget gt 12 dB on 62 5 125 um core clad fiber Wavelength 850 nm multi mode Optical Configuration Switch selectable Master Slave 2 2 Electrical Interface Electrical connector DB 9 male Interface type Switch selectable RS 232 pinout conforms to RS 232 RS 422 or RS 485 Bit Rate RS 232 0 to 115 2 KBPS RS 4XX 0 to 1 MBPS Interface Mode Switch selectable Unit can be configured to appear as a DCE or a DTE 2 3 General Specifications Indicators Four LEDs LTD Local Transmit Data FTD Fiber Transmit Data RD Receive Data COL Collision Power 12 VDC 500ma Environment 0 to 50 degrees Celsius Size 5 W x 5 3 Lx 1 7 H Page 6 of 10 3 0 Equipment Operation 3 1 Switch Options The Model 8277 is a versatile unit It has many switch selectable options that can be used to tai
7. lor it to different communications requirements The switches are located on the side panels The following tables list the switch selections and their functions Front Panel Switch Option DCE DTE DCE Pin 2 is an input into the unit and Pin 3 is an output DTE Pin 2 is an output and Pin 3 is the input into the unit 232 Selects electrical interface 232 is RS 232 422 485 232 and 422 is RS 422 or RS 485 Bottom Dip Switches DIP No FUNCTION Factory Settings 1 ON Connects pin 7 to pin 8 at the ON electrical interface CLOSE 2 ON Connects pin 4 to pin 9 at the ON electrical interface CLOSE 3 ON Close to terminate 4XX receiver ON CLOSE 4 ON Close for TDI Xmit Cont ON Open RTS controls Xmit CLOSE 5 ON Close for a 4 wire 422 OFF OPEN ON Close for 2 wire 485 OFF OPEN 7 ON Close for 4 wire 485 OFF OPEN ON Close for Optical Master Open ON slave CLOSE 3 2 Connections After the switches have been set properly the connections to the Model 8277 I O ports must be made There are three groups of connections These are the fiber optic interface the electrical interface and the power interface A minimum of two Model 8277s is required for communications The connections to the fibers are through two ST connectors on the rear of the Model 8277 These are marked T for optical transmit and R for optical receive The fibers between the two communicating Model 8277s
8. must be cross connected i e the optical transmitters must be connected to the optical receivers The Model 8277 s optical power budget is specified as 12 dB using 62 5 um core fiber The units may use fibers with other core diameters The table that follows specifies the loss budget for the different fibers Max Optical Loss Budget The connections to the electrical interface are through the DB 9 connector located on the rear of the Model 8277 The signals on these pins are shown in the tables that follow These signals as well as their functions and directions vary with the switch settings Proper connection requires at a minimum the use of TD RD and GND The tables that follow show the signal names and their sources for the various settings of the DCE DTE switch and the 232 4XX switch The Model 8277 is powered from an external transformer supplied with the unit The power transformer is plugged into 115 VAC and converts the 115 VAC to an unregulated DC voltage to be used by the unit The connection to the transformer on the Model 8277 is located on the rear of the unit A 220 VAC 50 Hz transformer is available as an ordering option Page 7 of 10 Page 8 of 10 Electrical Interface Pinouts RS 232 Switch in DCE position Signal Signal Signal Function Generated by Generated by Model Customer 8277 Pe fer a ED EA G a C Nes FO gt a a am E a a ae ee ete 2 GND ati ite RS 232 Switch in DTE position F
9. unction by Customer by Model 8277 ae ee eee a e a ees a a oa a eC po 8 TS XT Pp O pe SS GND SS RS 422 RS 485 4 wire Switch in DCE position Function Customer Equipment by Model 8277 RD I ss 4 Oooo pO RS 422 RS 485 4 wire Switch in DTE position Function Customer Equipment by Model 8277 RD ee i 26 2 o TDA i y to 8 CTS OOo y Oo o 9o as ee es PS 6ND o S Oooo O D 3 1 T 3 E 6 aa ie RS 485 2 wire Switch in DCE position Pin Signal Signal Generated by Signal Generated M Function Customer Equipment by wodsi 9277 PST TD RD PTR e o y O RSE N X e o a RTS J XX e PGND S RS 485 2 wire Switch in DTE position Function Customer Equipment by Model 8277 2 TD RD OTD RD 6 TD RD TD O RD Oo 8e Tts PX Po CTs PX PST GND o o ef Note When connecting to the Telebyte Model 285 the polarities of the TD and RD pins must be reversed Page 9 of 10 4 0 Indicators There are four LED indicators located on the front panel of the Model 8277 These indicators can be used to see the status of the Model 8277 and equipment connected to it Below is a list of the LEDs and their functions LTD Local Transmit Data This LED is used to monitor the data coming into the electrical interface from the user s equipment For RS 232 mode a positive voltage on the data entering the Model 8277 turns this LED on when either one of the following
10. yteusa com Warranty TELEBYTE warrants the equipment to be free from defects in material and workmanship under normal and proper use and in its unmodified condition for 12 months starting on the date it is delivered for use TELEBYTE s sole obligation under this warranty shall be to furnish parts and labor for the repair or replacement of products found by TELEBYTE to be defective in material or workmanship during the warranty period Warranty repairs will be performed at the point of manufacture Equipment approved for return for warranty service shall be returned F O B TELEBYTE factory and will be redelivered by TELEBYTE freight prepaid except for non continental U S A locations Non continental deliveries will be sent COD freight plus import export charges The above warranty is in lieu of all other warranties expressed or implied statutory or otherwise including any implied warranty of merchantability or fitness for a particular purpose TELEBYTE shall not be liable for any damages sustained by reseller or any other party arising from or relating to any equipment failure including but not limited to consequential damages nor shall TELEBYTE have any liability for delays in replacement or repair of equipment Out of warranty equipment may be returned to the Greenlawn NY customer service facility prepaid as described above Return shipping charges will be billed to the customer The repaired unit will have a 90 day warranty In those
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