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MFJ-1278B MULTI-MODE APPENDIX G: JUMPER FUNCTIONS
JUMPER FUNCTIONS AND LOCATIONS
The MFJ-1278B mother board has many jumper connectors. Each jumper connector has a
special function. The Jumper Function chart, Table G-1 in this appendix, will help in
identifying each jumper function. Figure G-1 will help in locating the jumper connectors
easily.
For normal operation a shorting jumper must be placed on the following connectors: JMP 5;
JMP 8; JMP 9 pins 2,3; JMP 13; JMP 14 pins 1,2; JMP 16 pins 1,3 and pins 2,4; JMP 18
pins 1,2; JMP 19 outside pair (one top,one bottom); JMP 22 pins 2,3; JMP 24 pins 1,2; JMP
26 pins 1,,2; JMP E, F, G, H. Also on the mode disconnect header J4 the following pins need
jumpers pins 1,2 11,12 13,14 17,18.
Table G-1: Jumper Function
Jumper # Position Function
JMP1 Pin 1 & 2 !DCD (RS-232C) stays on
Pin 2 & 3 !DCD (RS-232C) stays off
OFF (Default) !DCD reflects connect status
JMP2 Pin 1 & 2 (Default) 4.92 MHz CPU clock
Pin 2 & 3 2.46 MHz CPU clock
JMP4 ON Disable Tx watch-dog
OFF (Default) Enable Tx watch-dog
JMP5 ON (Default) Lithium battery connected
OFF Lithium battery disconnected
JMP7 ON Analog loopback mode
OFF (Default) Normal modem operation
JMP8 ON (Default) Demodulator enabled
OFF Demodulator calibrate
JMP9 Pin 1 & 2 Calibrate U16 tones
Pin 2 & 3 (Default) Normal modem operation
JMP10 ON Digital loopback mode
OFF (Default) Normal modem operation
JMP11 LEFT Transmit data NRZ
RIGHT (Default) Transmit data NRZI
JMP13 ON (Default) TTL, RTS enable
OFF TTL, RTS disable
JMP14 Pin 1 & 2 (Default) FSK out normal
Pin 2 & 3 FSK out reverse
JMP16 Pin 1 & 2 Without multi-gray levels