Specifications

S1 Position 4 (Unit A) and S3 Position 4 (Unit B): Receiver Squelch determines whether the corresponding modem's receiver is always on or is squelched by RTS. If receiver
squelch is enabled and RTS is high, the receiver will be squelched and RD and CD will be held low. This feature is useful for 2-wire operation, because the receiver and
transmitter are connected to the same pair of wires. (For 4-wire operation, both switches should be set to OFF--this is the factory default).
S1-4 Setting:
OFF (down) Receiver always on (default) for Unit A
ON (up) Receiver squelched for Unit A
S3-4 Setting:
OFF (down) Receiver always on (default) for Unit B
ON (up) Receiver squelched for Unit B
S2 (Unit A) and S4 (Unit B): 2-wire/4-wire operation determines whether the corresponding modem operates in 2-wire or 4-wire mode.
S2 Setting:
4W (down) Unit A operates in 4-wire mode (default)
2W (up) Unit A operates in 2-wire mode
S4 Setting:
4W (down) Unit B operates in 4-wire mode (default)
2W (up) Unit B operates in 2-wire mode
JP1 (Unit A) and JP2 (Unit B): Receiver Impedance. Use these jumpers to get the most efficient coupling of receivers to the transmission line, and therefore the greatest distance.
For point-to-point applications, both modems are normally set to Lo-Z. For multipoint applications, set the master and the most distant one or two slaves to Lo-Z, and the rest
of the slaves to Hi-Z. (The Mini Driver MP Card's transmitter can drive signals to as many a s 50 multidrop receivers, including one or two receivers set for low
impedance).
JP1 Setting:
Lo-Z (positions 1 and 2) Lo-Z (default) on Unit A
Hi-Z (positions 2 and 3) Hi-Z on Unit A
JP2 Setting:
Lo-Z (position 1 and 2) Lo-Z (default) on Unit B
Hi-Z (position 2 and 3) Hi-Z on Unit B
The Jumpers on the Interface Module:
The Mini Driver MP card is equipped with two RJ-11 line-interface ports and two 10-pin RJ-style serial-interface ports. Before you install the Card, you should examine the interface module you
have selected and make sure that it is configured for your application. Each interface module has five jumpers on its circuit board, as described below. The figure on the first page shows the
locations of the jumpers on the interface modules (the locations are the same for both the -RJ11 and -RJ45 models). These jumpers determine various grounding and signal characteristics for the
serial and modem-to-modem lines. The table below provides a summary of the functions of these jumpers. The functions are described in more detail afterward.
Jumper In Positions 1 and 2 In Positions 2 and 3
JB2
JB4
JB5
JB6
JB7
Line A Shield
Line B Shield
SGND tied to FGND
DSR A tracks DTR *
DSR B tracks DTR *
No Shield *
No Shield *
SGND not tied to FGND *
N/A
N/A
* factory-default settings