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M8 Standard


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Sound Card Interfaces 





M8 Standard Specifications

Overall Dimensions (maximum, w/o cables) 1.5 H x 5.5 W x 5.75 D inches
Weight (without AC adapter) 9 oz.
AC Power requirements (with supplied AC adapter) 120 Vac <1.5 watts
DC Power requirements (without supplied AC adapter) 13.8 Vdc nominal < 80mA
Frequency response, microphone input Direct coupled
Distortion, microphone input Direct coupled
Frequency response sound card input 100 Hz - 15 kHz, ± 1dB
Distortion sound card input Less than 0.1 % THD @ 1kHz
Input impedance (from sound card) 600 ohms resistive, minimum
Sound card level adjustment range -34 dB to > -120 dB
PTT max contact rating 2 A @ 24 V or 1 A @ 48 V
Serial interface (DB25F connector) Standard RS232
RS232 Pin Assignments (DB25 PC signal set)
  • Pin 4 Request To Send (PTT control)
  • Pin 5 Clear To Send (PTT interrupt)
  • Pin 6 Data Set Ready (PTT interrupt)
  • Pin 7 Signal Ground (isolated digital common)
  • Pin 20 Data Terminal Ready (PTT control)
The microphone audio is completely isolated from all other grounds. The sound card audio is isolated using an audio transformer. The serial and PTT circuits are isolated using, two DPDT relays, and an opto-isolator. A high grade DC blocking capacitor on sound card to mic. output is provided for use with radios that are designed for use with amplified or electret microphones.

The relays provide adequate current and voltage capability to switch tube rigs. The relays also provide automatic switching between sound card audio and the microphone plus our mic. override and mic. interrupt features.

Copyright 2002-2015, Universal Radio, Inc.