MCE-325 Programmable User Station
Installation 29
Bosch Security Systems, Inc.
Technical Manual
F.01U.193.228
Rev. 13
Auxiliary Connector, J22
4-wire CH A and B Input
The 4-wire CH A and CH B inputs are connected at the auxiliary connector as follows:
The 4-wire inputs must be assigned, using internal programming jumpers J19 and J20, before they can be used (as
previously described in “Intercom Line Channel Configurations (DS1-DS3, J6, J7, J19, and J20)” on page 21.
Key Outputs – Expanded IFB Option
Four (4) logic-type outputs are available at pins 6, 7, 19, and 20 of the auxiliary connector:
There are internal pull-up resistors on the CH 3 and CH 4 key outputs. Pressing the CH 3 and CH 4 talk button results in a
logic high to low transition at the corresponding key output. (Logic high is approximately 13VDC; Logic low is less than
2VDC.) There are no internal pull-up resistors on the CH 1 and CH 2 key outputs. These outputs float until externally loaded.
The CH 3 and CH 4 key outputs may also be used to expand the IFB functions, allowing any one (1) of several MCE-325 user
stations to interrupt a single-point program source and talk on the interrupted channel. For example, if one (1) MCE-325 is
operating with PROGRAM A assigned to CH 3, the CH 3 key output of a second MCE-325 user stations (with no program
connected) can be directly connected to the CH 3 key output of the first MCE-325; activating CH 3 for talk from either station
interrupts the program source and permits the station to talk on CH 3.
Remote Microphone Switch
A remote microphone switch may be connected at the auxiliary connector. Connect mic switch high to pin 24; connect mic
switch low to pin 10 or 11. When the switch is closed, the microphone turns on, and the front MIC ON LED illuminates. When
the remote switch is off, the microphone may be turned on from the front panel. When the remote switch is on, the microphone
cannot be turned off from the front panel.
TABLE 8.
Auxiliary Connector, J22
Pin #
Function
8
4-wire CH A high
21
4-wire CH A low
9
4-wire CH B high
22
4-wire CH B low
TABLE 9.
Auxiliary Connector, J22
Pin #
Function
6
CH 1 or 4-wire CH A key output
7
CH 3 or 4-wire CH B key output
19
CH 2 key output
20
CH 4 key output
