ZETRON 748, Technical Manual

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Operation
46 025-9368H
code programmed for encoding. This allows “cross-tone” encoding between tone and/or digital
codes.
Reserved Tone
The Model 748 has the ability to “reserve” a tone or code. If a tone/code is “reserved”, the
transmitter will be keyed, and a fast “busy” signal will be transmitted. This prevents that tone or
code from being used on the channel.
Tone-in-Tail
The Model 748 has the ability to continue to encode the current tone/code for the duration of the
transmit hold time. This can be enabled or disabled on a per tone/code basis. A typical use for this
feature is in systems that use “channel busy lockout” in the mobiles. When enabled, the mobiles
radio will remain unsquelched while the transmitter is keyed. This allows the mobiles involved in the
conversation to continue keying and unkeying. It also prevents other mobiles from barging in on the
channel.
Privacy
When this function is enabled, the Model 748 will not allow another tone/code to access the repeater
during the transmit hold time. This prevents other mobiles from “grabbing” the repeater during
momentary pauses in a conversation. If privacy is enabled, it is desirable to enable tone-in-tail as
well. This lets other mobiles know that the channel is busy. This feature can be enabled or disabled
on a per tone/code basis.
Courtesy Bip
This function, when enabled for a tone/code, will issue a prompt or beep out the transmitter
whenever the mobile unkeys. This is a 1200 Hz tone for a duration of 50 milliseconds.
Tail Bips
This function, when enabled (system wide) changes the Courtesy Bip from a single bip when the
mobile initially unkeys, to a bip once every second during the transmit hold time.
Transmit Hold Time
The Model 748 has a separate transmit hold time for each tone/code. There is also a separate
transmit hold time for the initial keyup of a validated tone/code. The first keyup of a validated
(enabled) tone/code uses
Initial TX hold time for the transmit hold time. All subsequent keyups (until
the transmit hold time expires and the Model 748 unkeys) of the validated tone uses the TX hold time
for the decoded tone/code.
Morse ID
Each tone/code may be assigned an eight-character Morse code ID. This will be automatically sent
(during the transmit hold time) when a mobile keys up after the an interval timer has expired. The
ID
rate sets the interval for all tone/code ID's. The ID is transmitted at a reduced level so that voice