Service manual

TP0332/2 C.1
SRP8000 SERIES VHF/UHF PORTABLE RADIO
APPENDIX C - HEADSET
Figure C.1 Headset
INTRODUCTION
The headset supported by the SRP8000 series portable radio is a single earpiece headset with
boom microphone, in-line PTT switch and a VOX PTT function.
The headset is connected to the portable radio via a 1,5m straight cable with a 2,5mm (J1) and
3,5mm (J2) stereo jack plugs mounted in a single moulding.
Terminology
In the following text, switch states and jack connections are defined as follows:
SPECIFICATION
Microphone
Maximum circuit current 10mA.
Type Electret.
Impedance 2,2kΩ.
Sensitivity –58dB ±3dB at 1kHz (0dB = 1V / µbar).
Sensitivity variation relative to 1kHz over Less than +10dB, –2dB.
frequency range 300 Hz to 4kHz.
PTT switch Push to transmit.
DC voltage overshoot during switching periods Within 2% of nominal voltage.
PTT ‘click’ suppress circuit:
DC voltage establishment time for Less than 5ms to reach 95% of the nominal PTT
active PTT voltage.
DC voltage established time for PTT 50ms ±20% to reach 95% of the nominal PTT
release release voltage.
Sleeve
Ring
Tip
Switch ‘closed’
Switch ‘open’