D1.4 General Information M8SL2-00-002-812
© Copyright Tait Electronics Limited August 2004. All rights reserved.
this application the notch filters (which ordinarily remove the key tone from the
audio path) must be turned off using PGM800Win so that the keying signal is
propagated to the end transmitter.
1.1.2 Alarm Monitoring and Confirmations
The T803 monitors three T800 sub-rack alarms (transmitter forward and reverse power,
and low battery/power supply), one line alarm (line fail indication) and four external
closure alarms. If alarms are triggered the T803 can be programmed to generate tone
sequences (DTMF, Selcall or function tones) and/or enable auxiliary outputs, to alert
system users of a problem. The tone sequences can be sent to line and/or radio.
Additionally the T803-02 can be programmed to respond to as many as eight different
non-alarm triggers. These can be used as confirmation that an event has occurred. Con-
firmations can be programmed to occur in the event of power-up, channel change and/
or the detection of up to six user defined function tones. In the same way as for alarms,
the T803 can generate tone sequences and/or enable auxiliary outputs as a response to a
confirmation.
1.1.3 Voting Tones
The T803 can also generate voting tones where a 4-wire line interface is used. Voting
systems are used where several base station receivers are tuned to the same radio chan-
nel and located at different sites, sending audio back to a central control where the best
quality audio must be selected or “voted upon”. Tone on Idle or Sliding Voting Tones
can be generated to interface a T800 sub-rack to a wide variety of industry standard
Radio Voting systems.
In Tone on Idle applications, a tone (normally the same frequency as LLGT) is transmit-
ted to line when the T800 receiver is muted. When the tone disappears, control room
equipment can perform signal to noise measurements on incoming audio lines and
select the best for feeding to the control room user.
In Sliding Voting Tone systems, a tone is transmitted to line whose frequency is propor-
tional to the T800 receiver’s RSSI. Control room equipment determines which receiver
has the highest RSSI and thus selects which line carries the highest quality incoming
audio.
1.1.4 Other Features
• Programmable Morse Code Encoder for automatic station identification (CWID)
• User programmable Line levels
• Programmable Transmit and Receive audio path delays
• Programmable (on/off) notch filtering.
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