Codan Radio MT-3 - Manual (Page 19)

MT-3 ANALOG RADIO SYSTEMS | USER GUIDE
Chapter 2: Technical Information Page 11
OTHER SETTINGS AND CONFIGURATIONS
The MT-3 Radio System has a wide array of settings and confi gurations that can be adjusted or turned
on and off. The main confi guration of the radio system is set in the Audio Control Card, however
additional settings may be found throughout the system.
Hang Timer
The hang timer will keep the transmitter keyed once the receiver COR line has gone inactive. The hang
timer can be turned on and off by setting jumpers in the Audio Control Card, and the length of the hang
timer can be adjusted by variable resistors in the Audio Control Card.
Time Out Timer
The transmitter module contains a programmable PTT time out timer circuit. The time out timer will
count down when the transmitter is keyed (PTT active). The timer will shut the transmitter output off
once the timer has expired. To reset the timer, the PTT input must go to an inactive state. The time
out timer is designed to reduce battery draw during a “stuck microphone” condition, by turning off the
transmitter after a set period of time. The time out timer duration is jumper selectable in the transmitter
module from 1 second to 8 hours (default 5 minutes). The time out timer can also be enabled or
disabled on the subrack / motherboard by selecting a jumper position. The jumper is labeled PTT WTO
(With Time Out) or PTT NTO (No Time Out).
Pre-emphasis and De-emphasis
The selection of fl at or pre-emphasis audio is jumper selectable on the audio processor board in the
transmitter module. The fl at and pre-emphasis audios require slightly different tuning procedures to set
up properly. The selection of fl at or de-emphasis audio is jumper selectable in the receiver module for
the 600 ohm balanced output. The receiver also has two additional signal lines dedicated to fl at and
de-emphasis audio output. In most confi gurations, the de-emphasis audio signal line drives the System
Regulator speaker and the fl at audio signal line is not used.