Shure 888TT User's Manual
Contents
1. Dimensions See Figure 2 1 9mm j IN 42 6 MM _ 1 11 16 IN A 36 9 mm 15 32 IN I ol 101 mm 3 31 32 IN 40 4 mm Mena 1 19 32 IN 2 70 mm 2 3 4 IN 44 4mm gt 1 3 4 IN lt OVERALL DIMENSIONS FIGURE 2 Net Weight including cable and connector 283 g 10 oz Certification FAA Certified for aircraft under TSO C58a requirements FAA CERTIFICATION The Model 888TT is FAA Certified for aircraft use under FAA TSO C58a requirements To maintain this FAA Certifi cation any service required for the Model 888TT must be performed by Shure Brothers Incorporated or by an FAA Approved Service Facility MOUNTING The 888TT is equipped with a rear case hang up loop and a hang up button for use with a mounting bracket on associated equipment Heavy duty chrome plated mounting brackets are avail able in quantities of three as Shure Part No RK6MB CABLE To attach the cable to the 888TT insert the modular tele phone type plug in the microphone jack until it locks To re move the cable from the microphone insert the small screwdriver supplied with the 888TT in case hole A just above the cable jack see Figure 4 to unlock the plug and withdraw the plug from the jack Microphone connector wiring is shown in the table below Microphone Connector Wiring ear unesen2. 20 50 100 200 500 1 000 2 000 5 000 10 000 20 000 FREQUENCY IN Hz TYPICAL FREQUENCY RESPONSE FIGURE 1 Polar Pattern Bidirectional noise canceling Electrical Characteristics Operating Voltage Notes Audio Output Level Audio trim 100 ubar acoustic 11 5 dBV 11 0 dBV 10 0 dBV potin factory test signal at 1 266 mV 281 mV 316 mV preset posi kHz 10 mm tion DTMF Output Level 12 8 dBV 12 0 dBV 11 2dBV DTMF trim 230 mV 250 mV 275 mV potin factory preset posi tion Standard electrical test circuit per RTCA DO 170 tMicrophone is powered only while PTT switch is depressed standby current 0 if PTT switch is released Environmental Conditions Operating Temperature 40 to 60 C 40 to 140 F Storage Temperature 54 to 85 C 65 to 185 F Relative Humidity 0 to 95 non condensing Microphone Connector 6 conductor modular telephone type PTT Switch assembly Mechanical Double pole single throw leaf type nor mally open Cable ALM 88 detachable MODULINK 0 65 m 2 1 ft coiled 1 8 m 6 ft extended cord with modular plug on micro phone end and PJ 068 aircraft connector on equipment end Construction Case Black textured high impact ARMO DUR Switch Button Black ARMO DUR Keypad Molded silicone rubber Hangup Loop Matte finish stainless steel
3. ra Function Black PTT Switch Pin Ground 2 White Dc Bias Audio Out Audio Out Ac coupled 3 PTT Switch Ground 4 N C The ALM 88 cable is wired at the microphone connector as shown in Figure 3 at the bottom of the page ADJUSTMENTS Operation of microphone and DTMF functions requires that the 888TT be connected to the communications equip ment and that the equipment power is turned on After connection to the communications set turn the equipment power On Power application can be verified by pressing the push to talk switch and observing the keypad LED backlighting Factory preset microphone audio and DTMF levels are correct for aircraft radios with standard input circuits as defined in RTCA DO 170 and level adjustment should not ordinarily be necessary When such adjustment is neces sary it should be performed only by Shure Brothers Inc or by an FAA Approved Service Facility Use the supplied screwdriver to adjust the microphone sensitivity and DT MF output levels as follows 1 Microphone sensitivity Press the push to talk but ton and speak normally into the microphone while checking transmitter modulation Adjust the micro phone sensitivity control case back hole B in Figure 4 and repeat the talk test as required DTMF LEVEL ADJUST C MICROPHONE SENSITIVITY ADJUST B CABLE RELEASE A MICROPHONE CASE BACK FIGURE 4 2 DTMF output Press and hold the push to talk butt
4. Shure Brothers Incorporated 222 Hartrey Avenue Evanston IL 60202 3696 U S A Model 888TT User Guide ara ee eee DTMF AIRCRAFT MICROPHONE The Shure Model 888TT is handheld amplified noise cancelling DTMF communications microphone that is FAA Certified for aircraft application TSO C58a In addition to its extremely clear transmission even in noisy environ ments the 888TT has very low sensitivity to hum pickup and low susceptibility to radio frequency interference In instances where transmitter input gain requires micro phone sensitivity modification the 888TT has limited ac cess external screwdriver controls for independent adjust ment of both mic audio and DTMF levels This eliminates the problem of fixed audio levels that require disassem bling the microphone for adjustments Restricted control access however prevents accidental changes common to other types of external controls The microphone has an illuminated keypad made of tough silicone rubber with durable printed characters that will last the life of the microphone The keypad is backlit by red LEDs easily visible during night operation minimizing eye readjustment for night vision The 888TT is designed for use with most currently avail able aircraft radios For installation convenience all micro phone and signaling functions including keypad illumina tion are powered directly from the microphone input circuit of most transmitters reducing the ne
5. ching to radio equip ment or other surfaces are available in quantities of three as Shure RK6MB Features e FAA Certified for aircraft use e Detachable MODULINK modular plug coil cord with PJ 068 aircraft radio plug e Noise canceling with frequency response tailored for optimum intelligibility e Top Talk Sound Channel for clear voice input easy handling e Built in transistor amplifier powered by carbon micro phone type circuit e Illuminated keypad with positive tactile confirmation and audible verification tones e Convenient screwdriver accessible microphone gain adjustment accommodates most input circuits e Simple easy to use continuous tone dialing e Screwdriver accessible DTMF level adjustment inde pendent of microphone gain setting e Low sensitivity to hum and rf interference e Rugged Million Cycle Plus leaf type switch stands up under severe environments and constant use e High impact ARMO DUR case strong lightweight comfortable to the touch in hot or cold environments e Rugged and dependable under all operating condi tions 1998 Shure Brothers Incorporated 27A3041 RL Printed in U S A SPECIFICATIONS Type Electret condenser noise canceling with transistor pre amplifier DTMF signaling circuitry illuminated keypad Frequency Response 200 to 4 000 Hz see Figure 1 Oo Oo an RELATIVE RESPONSE IN dB
6. ed for equipment modification A three conductor MODULINK cable sold separately has a telephone type modular plug with an ef fective strain relief to connect to the microphone and a PJ 068 plug on the equipment end for connection to most aircraft radios This cable can be instantly changed or re placed without soldering The 888TT is ergonomically designed it fits naturally and comfortably in the hand and is not affected by heat or humidity The voice entry port is at the top of the micro phone body for simple natural transmitting The rugged ARMO DUR case is immune to oil grease most fumes and solvents salt spray sun rust and corrosion The 888TT is outstanding in its ability to withstand mechanical shocks and vibration Its Million Cycle Plus leaf type switch is a double pole single throw type designed to re sist the effects of severe operating conditions and constant use It has nickel silver blades with palladium alloy con tacts for reliable oxidation free operation The microphone is supplied with output levels factory preset to meet TSO C58a requirements Adjustments should be made only by an FAA Approved Service Facility or the Shure Service Department The 888TT is supplied with a small screwdriver for re leasing the modular plug microphone cable from the case and for adjusting the microphone amplifier gain and DTMF level A mounting loop is supplied affixed to the micro phone and mounting brackets for atta
7. on Depress and hold down a keypad button for a continu ous tone Adjust the DTMF output control case back hole C in Figure 4 as required OPERATION Voice Transmission 1 Hold the microphone comfortably in the hand posi tioned so that the Top Talk Sound Channels at the top of the case are near the mouth The clearest sound is often obtained with the microphone at the corner of the mouth with the cable away from the face 2 Depress the push to talk button and make sure the equipment is in the transmit mode before speaking Dialing 1 Press and hold the push to talk button 2 Press the desired keypad buttons in sequence A high pitched tone will confirm that the code has been trans mitted The microphone audio is muted during DTMF tone transmission REPLACEMENT PARTS Modular plug cable with PJ 068 plug assembly ALM 88 FURNISHED ACCESSORY Screwdriver oni Biss Pe a BS aS 65A1587 OPTIONAL ACCESSORY Mounting Bracket 3 in kit 0 RK6MB DRAIN 5 SLEEVE GROUND DRAIN N m RED ze BLACK 5 BLACK RING AUDIO BLUE BLUE Nc TIP PTT o YELLOW_ YELLOW F WHITE N R WHITE UJ PJ 068 CONNECTOR TO RADIO RJ11 CONNECTOR TO MICROPHONE MODULINK CABLE WIRING FIGURE 3 ENVIRONMENTAL QUALIFICATION FORM TSO C58a DO 170 PARA CONDITIONS DESCRIPTION OF TESTS 3 1 1 G
8. or an experienced radio TV technician for help
9. round Survival Low Tempera 4 5 1 Microphone tested to Category D1 ture and Operating Low Tem perature 3 1 2 Ground Survival High Temper Microphone tested to Category D1 ature and Short Time Operat ing High Temperature Operating High Temperature Microphone tested to Category D1 3 1 3 Altitude 7 5 1 Microphone tested at altitude equivalent to 15 200 m 50 000 ft 11 6 kPa 116 mbar 87 mm 3 42 in Hg 3 1 4 Decompression Microphone tested at altitude equivalent to 15 200 m 50 000 ft 3 1 5 Overpressure Microphone tested at pressure 170 kPa equiv alent altitude 15 000 ft 2 11 amp Temperature Variation Pre Microphone tested to Category B for two cycles 3 2 amplifier 3 3 Humidity Microphone tested to Category A for 2 cycles 3 5 Vibration 55 Microphone tested to Categories N B amp M Table 8 1 Not on Vibration Isolators 3 6 Magnetic Effect 15 3 Microphone tested to Equipment Class Z no magnetic properties 3 7 Voltage Spike Conducted Microphone tested to Category A 3 8 1 Induced Signal Susceptibility Microphone tested to Category Z 3 9 Radiated rf Susceptibility 20 5 Microphone tested to Category A 3 10 Emission of rf Energy Microphone tested to Category Z 3 11 Final Distortion After all required environmental tests micro phone meets requirements of DO 170 2 2 3 12 Push To Talk Switch Life After all required environmental tests micro Fire Retardance Tests performed at Radiometric
10. s Midwest Corporation Lombard IL Tested to DO 160B Tests performed at Downers Grove IL Elite Electronic Engineering INFORMATION TO USERS This equipment has been tested and found to comply with the limits for a Class B digital device pursuant to Part 15 of the FCC Rules These limits are designed to provide reasonable protection against harmful interference in a residential installation This equip ment generates uses and can radiate radio frequency energy and if not installed and used in accordance with the instructions may cause harmful interference to radio communications Howev er there is no guarantee that interference will not occur in a particu lar installation If this equipment does cause harmful interference phone meets requirements of DO 170 Appendix B T 7 and 2 9 In accordance with FAR 25 25 869 a 4 and Appendix F Part a 3 b Tests performed at Chicago IL All other tests performed at Shure Brothers Evanston IL Gaynes Test Laboratories Inc to radio or television reception which can be determined by turning the equipment off and on the user is encouraged to try to correct the interference by one or more of the following measures Reorient or relocate the receiving antenna Increase the separation between the microphone and receiver Connect the microphone transmitter into an outlet on a circuit dif ferent from that to which the receiver is connected Consult the dealer
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