Product manual

Installation
20 025-9158L
JP1 (RAM SELECT)
This jumper selects the size of the on board RAM. There are three choices:
Position A = 32K RAM
Position B = 8K RAM
No Jumper = 8K RAM
All Model 26s use 32K RAM. This jumper should always be in the A position.
JP2 (FFSK RCV SELECT)
This jumper enables/disables the automatic gain control (AGC) circuit for FFSK signals.
There are three choices:
Position A = Enable the AGC circuit
Position B = Disable the AGC circuit
No jumper = Prevents reception of data from the Model 6s
The normal position for JP2 is the Disable position (B). The FFSK modem chip that
receives this signal has its own gain control circuit. This jumper must always be installed
for the Model 26 to communicate with the Model 6.
JP3 (VOX CONTROL)
This jumper enables/disables the VOX circuit. There are three positions for this jumper:
Position A = Enable VOX
Position B = Disable VOX
No jumper = Enable VOX
The position of JP3 depends on if the COR input is used. Both the VOX and COR input
signals are put through an “OR” gate and then read by the microprocessor. If external
connections are made to the COR input, then JP3 should be in the B position to disable
VOX. If COR is not being used, JP3 should be in the A position to enable VOX, and
jumper JP8 should also be in the A position to pull-up the COR input.
JP4 AND JP5 (MODEL 26 CHAIN BAUD RATE)
These two jumpers control the baud rate used by the Model 26 “CHAIN” interfaces when
multiple units are linked together. The baud rates available are 2400, 4800, and 9600.
Normally there are no jumpers installed for JP4 and JP5. A trace on the PCB defaults the
baud rate to 9600. If another baud rate was needed you would cut this trace and install
jumpers in the appropriate positions.