M-175 OPERATOR’S MANUAL M-175 Personal Communication Transmitter 357 West 2700 South • Salt Lake City, Utah 84115 • Phone: (800) 496-3463 • Fax: (801) 484-6906 • http://www.comtek.
TABLE OF CONTENTS Introduction ........................................................... 1 Setup ............................................................................... 2 Controls .................................................................. 3 Battery Removal / Replacement ...................................... 4 Battery Charging ...................................................... 5 Auxiliary Audio Input Operation ................................... 6-7 Snap-On Belt Clip .....
INTRODUCTION M-175 Personal Communication Transmitter T he M-175 personal transmitter is a professional quality, compact body-worn transmitter designed for reliable one-way remote communication. It’s ideal for many applications including: personal cueing, assistive listening, tour guide presentations, communication for on-the-job training, (requiring being some distance away or in a noisy environment), and other personal, one-way remote communication situations.
M-175 SETUP Setup a. Check to ensure that the M-175 transmitter’s radio frequency channel is the same as the associated COMTEK receiver’s channel. (Channels are indicated by the rotary channel selector switches on the back of the transmitter. See page 8.) b. Open the battery door cover on the transmitter (see page 4) and insert a new nine volt alkaline battery (Eveready E522 or equivalent). This type of battery will offer up to 14 hours of operation.
M-175 CONTROLS n CHANNEL SWITCHES: These rotary switches are used to set the transmitter to the desired operating frequency. (See page 9 and 10 for frequency selection chart.) oBATTERY COMPARTMENT: The battery compartment features a hinged battery cover and an alignment system that ensures proper battery polarity. Battery installation and removal is facilitated by simply manipulating the bottom of the battery.
M-175 BATTERY REMOVAL / REPLACEMENT Low Battery Indicator The LED on the top of the transmitter indicates the status of the battery as well as indicating that the unit is turned on. When the transmitter is turned on, the LED illuminates. If the battery is low, the green LED will blink rapidly to warn you that the battery will soon be dead. Replace a low battery immediately. Battery indicator LED Battery Removal / Replacement Pull back battery door latch and allow battery cover door to spring open.
M-175 BATTERY CHARGING Battery Charging 1. Make sure that a seven cell 9 volt Ni-MH rechargeable battery is used with a minimum of 200 mAh capacity. (Alkaline batteries must not be charged.) TANT IMPOR 2. Make sure the M-175 is turned OFF. 3. Note that the red charging indicator on the charger is ON when the M-175 is plugged into the charger through the audio output jack. 4. When using the NBC 9-2C charger allow the battery to charge for 14 hours for a full charge. Unit must then be unplugged.
M-175 AUXILIARY AUDIO INPUT OPERATION Auxiliary Audio Input Operation The M-175 transmitter may transmit from a variety of audio sources such as digital media players, or any audio device having an auxiliary or earphone level audio signal. The auxiliary input cable supplied with the M-175 transmitter (CB-36 ST) will operate with any device having a mini 3.5 mm jack, stereo or mono, and with line level or earphone level output.
M-175 AUX OPERATION (Cont.) / SNAP-ON BELT CLIP c. Turn on the transmitter with program from the audio source being fed to the transmitter. Observe the audio “voice” level modulation indicator. A full bright LED indicates full audio compression at 100% modulation. For best performance, the audio input gain should be adjusted for some low level LED luminescence during normal audio levels with occasional full bright peaks indicating 100% modulation. d.
M-175 FREQUENCY SELECTION Frequency Selection (72-76 MHz) The M-175 transmitter can operate on one of 88 available channels between 72-76 MHz. COMTEK channel designations indicate both standard non-companded channels and high-fidelity companded channels. Channels 1-88 are to be used only with receivers having 2:1 audio companding processing. Channel position 91-00 is to be used only with receivers having linear non-companded audio processing.
M-175 FREQUENCY INFORMATION 72-76 MHz STANDARD COMPANDED CHANNELS CHAN 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 FREQ 72.02 MHz 72.04 MHz 72.06 MHz 72.08 MHz 72.10 MHz 72.12 MHz 72.14 MHz 72.16 MHz 72.18 MHz 72.20 MHz 72.22 MHz 72.24 MHz 72.26 MHz 72.28 MHz 72.30 MHz 72.32 MHz 72.34 MHz 72.36 MHz 72.38 MHz 72.40 MHz 72.42 MHz 72.46 MHz 72.50 MHz 72.54 MHz 72.58 MHz 72.62 MHz 72.64 MHz 72.66 MHz 72.68 MHz 72.70 MHz 72.72 MHz 72.74 MHz 72.
M-175 FREQUENCY INFORMATION (Continued) M-175 LETTER CHANNELS (72-76 MHz) GROUP 1 CHANNEL Standard Non-Companded Channels (For PR-72b and PR-75) CHANNEL FREQUENCY 91 92 93 94 95 96 97 98 99 00 A 72.1 MHz B 72.3 MHz C 72.5 MHz D 72.7 MHz E 72.9 MHz F 75.5 MHz G 75.7 MHz H 75.9 MHz I 74.7 MHz J 75.3 MHz 91 95 98 00 FREQUENCY A E H J 72.1 MHz 72.9 MHz 75.9 MHz 75.3 MHz GROUP 2 CHANNEL FREQUENCY 92 97 99 B 72.3 MHz G 75.7 MHz I 74.7 MHz GROUP 3 CHANNEL FREQUENCY 93 96 C 72.5 MHz F 75.
M-175 P-7 OPTION MBS-216 Mounting Bracket The optional MBS-216 mounting-bracket stand is an ideal way to conveniently position the M-175 Option P-7 transmitter for field use. The M-175 clip snaps into the mounting bracket locking the transmitter in place. The MBS-216 maintains a vertical antenna position, maximizing the performance of the M-175 Option P-7 transmitter.
M-175 OPTIONAL ACCESSORIES Optional Accessories 1. NBC 9-2C Battery charger 2. NBC 9-3-1 Digital fast charger 3. NBC 9-3-12 Digital 12-station fast charger 4. NH9-200 Rechargeable batteries 5. BC-216 Snap-on belt clip (supplied with M-175) 6. P1 Universal pouch 7. SM-185 Unidirectional electret condenser microphone 8. PSC-HM Headworn unidirectional electret microphone Auxiliary Audio Input Cords 9. CB-36 STM Stereo mini 3.5 mm (supplied with M-175) 10. CB-36 RCA Phono plug (optional) 11.
M-175 TROUBLE SHOOTING Batteries and Battery Charging If... Test indicator lamp doesn’t illuminate when units are turned on... Then... • If rechargeable batteries are used, ensure that they have been allowed to charge at least 14 hours to a full charge. Verify that the charging indicator lamps are illuminated when the charging plugs are plugged into the units. The units’ power switches must be in the “off ” position for charging.
M-175 TROUBLE SHOOTING (Continued) Possible Causes of Noisy Audio 1. Excessive Distances Operating at distances greater then 200 ft. may cause some intermittent noise. 2. Channel Selection For operation with non-companded receivers (such as PR-75 or PR-72), the M-175 transmitter must be set to one of 10 non-companded channels 91-00. For high-fidelity operation, the companded channels 1-88 must be used with companded receiver PR-216/72MHz model. (See page 9 for Frequency Information.) 3.
M-175 SPECIFICATIONS Audio Input: • Microphone input impedance for electret type microphone - 3000 ohm • Aux/Line input impedance - 10 k ohm at 0 dBV nominal Connectors: Microphone - Micro-mini mono 2.5 mm Auxiliary - Mini stereo 3.5 mm Audio: Tip and sleeve Battery Charging: Tip and sleeve Out-of-Band Emissions: Better than 50 dB below carrier R.F.
M-175 WARRANTY AND SERVICE Warranty COMTEK transmitters and receivers are warranted to be free from defects in workmanship and material under normal stand-alone use and conditions for a period of two years from date of original purchase. Items such as headphones, earphones, neckloops, and cords are warranted to be free from defects in workmanship and material for a period of 90 days from the date of original purchase. Batteries are not covered by this warranty.
357 West 2700 South • Salt Lake City, Utah 84115 • Phone: (800) 496-3463 • Fax: (801) 484-6906 • http://www.comtek.
