Clear-Com AB-120 - Manual (Page 15)

Clear-Com Communication Systems
AB-120 Announcer Console Instruction Manual
1 - 9
Jumper Options
There are eleven two position jumpers that provide many options for
the operation of the AB-120. To access these jumpers, remove the
bottom cover of the unit. Inside the bottom cover is a label describing
the functions of jumper and switch.
Note: Jumpers 2, 3, 4 and 6 are not used.
JP1
JP1 provides termination for the intercom line if needed. The AB-120 is
always a remote intercom station and therefore does not provide
termination for an intercom line. The termination is provided for the
cases where the party-line output of the AB-120 is not used and the
party-line drive circuit needs termination to be stable and not oscillate.
As shipped from the factory, the jumper is between pins 1 and 2 of JP1
making the termination inactive. To activate termination, place the
jumper between pins 2 and 3.
JP7
JP7 allows the send gain on the talkback channel to be increased
when driving a TW type intercom line, such as RTS. Placing the
jumper between pins 2 and 3 increases the send gain approximately 4
dB. JP7 is shipped from the factory with its jumper between pins 1 and
2, providing Clear-Com standard levels to the intercom line.
JP8
JP8 provides the selection of desired output level for the microphone
output.
JP9 and JP10
These JPs provide selection of the desired output level for the
microphone output.
JP11
JP11 selects the sportscaster or announcer modes of operation for the
front panel push button switches. Connection between pins 1 and 2
enables the sportscaster mode and connection between 2 and 3
enables announcer mode.
Microphone Output Pad
The microphone output connector on the rear panel can be internally
plugged into two different headers on the main PCB. Connecting the
output to J2 provides a high level of output. Connecting the output to
J3 adds a 30 dB pad in the series to provide a lower level output.