Product manual

Operating the Model 26
94 025-9158L
programmed to show input status. Sense inputs can have only two states, active or
inactive. One LED pair can display the status of two sense inputs. The LED combinations
used by the Model 26 to indicate the current state of sense inputs are selected by the
customer when the system is ordered.
Back Panel LEDs
There are two LEDs on the back panel of the Model 26: COR/VOX and PTT. These two
LEDs deal with Model 6 communications. They are used during installation of the system
and to diagnose communication problems if they arise.
COR/VOX LED
This LED represents the receiver state that is currently read by the microprocessor. Its
state is affected by both the RX COR+ input and a VOX detect circuit in the Model 26.
Only one of these circuits should be operating (refer to
JP3 (VOX CONTROL) on page
20and JP8 (COR INPUT POLARITY) on page 21). There are two potentiometers that
adjust the sensitivity of the LED (refer to COR and VOX in the
Adjustments section
starting on page
56).
The VOX circuit is enabled only if the Model 26 is running in either Wire Line or VOX
communications mode (refer to
Communication Mode on page 34). When this LED is on
and VOX is enabled, it indicates that the Model 26 is receiving something. If the Model
26 is receiving and in VOX communications mode, it will not transmit.
The COR circuit is enabled only if the Model 26 is be running in either COR or Trunking
modes.
If this LED is on, then the Model 26 is receiving a logic low signal on its RX COR+
input. If the communications mode is set to “COR, TX on COR High”, the Model 26
assumes the channel is busy and does not transmit. When the LED is off, the Model 26
assumes the channel is clear and it will transmit.
If this LED is off, then the Model 26 is receiving a logic high signal on its RX COR+
input. If the communications mode is set “COR, TX on COR Low”, then the Model 26
assumes the channel is busy and does not transmit. When the LED is on, the Model 26
assumes the channel is clear and it will transmit.
In either one of the COR communications modes the LED indicates channel activity at
the RX COR+ input. As can be seen from the preceding discussion, it may be either on or
off when receiving, but the changing states are a measure of the received signal activity
to the Model 26. This is not the case when either of the trunking modes is used.
If this LED is off, then the Model 26 is receiving a logic high signal on its RX COR+
input. If the communications mode is “Trunking, Chan Grant on High COR” and the
Model 26 has requested a channel for transmission by grounding its PTT signal (and the