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MFJ-1278B MULTI-MODE HARDWARE
JUMPER FUNCTIONS
The following table lists the function of each jumper on the MFJ-1278B. 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 8-1: 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