Product manual

Electrical Connections
29
J13 Connector
This connector is the inside connector of the two on the left side of the rear panel. The
following are the pin descriptions:
Pin Description
1
(XBUSY+)
This input, when driven low, prevents the Model 26 from beginning to transmit.
It is typically connected to a XBUSY output from a console, to prevent the
Model 26 from sending data packets while a voice dispatch in being made on
the channel.
2
(XBUSY-)
This is connected to the chassis ground of the Model 26.
3
(+AUD 4W RX)
This is the positive side of the 4-wire, transformer coupled, audio input. JP9
sets the input impedance for this input and potentiometer “4W RCV” (R69)
adjusts the audio input level.
4
(-AUD 4W RX)
This is the negative side of the 4-wire transformer coupled audio input. Refer to
the description of pin 3 above.
5
(RX COR +)
This input, when connected to a radio Carrier Operated Relay (COR) output,
gives the Model 26 an indication of when the radio is receiving a carrier signal
(channel busy). It can also be used as an input for a “Channel Grant” signal in a
trunked radio system. Potentiometer “COR” (R32) adjusts the threshold level
and “COR/VOX” LED can be used to monitor its state. Jumper JP8 is also
associated with this input (see
JP8 (COR INPUT POLARITY) on page 21), as
well as the Communications Mode selection in the Software Configuration
program (see
Conventional Radio - TX on COR Communication Modes on page
37).
6
(RX COR-)
This is connected to Model 26 chassis ground.
7
(DATA MUTE)
This signal is used to signal a dispatch console when an FFSK packet is being
received or transmitted. This is an open collector output. Its active state polarity
is set in the Software Configuration Program by the “Data Mute Active
Polarity” parameter (see
System Configuration Menu on page 33). It is typically
connected to the XBUSY or BUSY MUTE input on a dispatch console to
prevent unwanted FFSK packet noise from being heard in the console speakers.
This signal and the PA READY signal perform similar functions, but in
different ways. This signal goes active whenever an FFSK packet is either
received or transmitted by the Model 26.
There are two parameters in the System Configuration Menu that affect this
signal. The duration of its active state is set by the “FFSK Mute Debounce”,
and the active state time interval preceding a Model 26 transmission is adjusted
by the “Keyup Delay”.