M8SL2-00-002-812 General Information D1.3
© Copyright Tait Electronics Limited August 2004. All rights reserved.
1.1 Introduction
The T803-02 is a tone-operated Remote Controller otherwise known as a Tone Remote.
Features include alarm monitoring, voting tone generation and simple high site control.
It interfaces either a 2-wire or 4-wire line circuit to the T800 SL2 Base Station and thus
enables a dispatch console (also known as a desktop controller) to monitor and control
the remote basestation. The T803-02 interfaces with the SL2 receiver and transmitter via
the backplane PCB (X800-56-PCB3) and two small flat cable looms plugged into the D-
ranges on the back. The T803 is configured using the Tait PGM800Win programming
software (V4.02 and later) on a PC.
1.1.1 Tone Remote
The T803 tone remote enables a remotely located user to:
• key the transmitter
• defeat the receiver’s CTCSS mute (to monitor a channel)
• change the set channel (up to 256 channels)
• change between base station and repeater modes (repeater knockdown)
• monitor and cancel alarms
• turn repeater site equipment on or off (highsite control)
• loop back line audio (4-wire line interface only)
This is achieved using three industry-standard tone signalling plans for ease of integra-
tion into existing control systems and choice of vendor for office/control room equip-
ment. These plans are:
• EIA tone remote using a single function tone.
In this system when the control room user presses the transmit key, the line con-
trol equipment sends a 120ms long burst of high level guard tone (HLGT – usually
2175Hz at +10dBM to line). This is followed by a single 40ms function tone at
0dBm to line. The available tone set is 650Hz to 2050Hz in 100Hz steps. This func-
tion tone can change channel, monitor the radio channel (defeat receiver CTCSS)
or a variety of other functions. Following these initial tone bursts a low level
guard tone (LLGT – usually 2175Hz at –20dBm) is sent to line and speech is gated
onto line (at approx 0dBm peak level). This continues until the user releases the
transmit key. This removes speech from the line and low level guard tone ceases.
• EIA enhanced tone remote using two function tones.
This is a variant of the above system where two function tones are sent one after
the other in the period between the high level guard tone and the low level guard
tone. The tone set is also expanded (650Hz to 2050Hz in 100Hz steps) to give 225
possible combinations which can be allocated to various actions. The duration of
both high level guard tone and function tones can be varied.
• Simple Transmitter keying using low level guard tone.
This is used where complex functionality is not required. One application is to key
a link transmitter where the high level guard tone, the function tones, speech and
low level guard tones are transparently carried to an end base station. Note that in
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