2070-9x User’s Manual
Page 10
handshaking signals RTS and CTS.
The 496 needs to have the RTS signal
before it will transmit. In a 4-wire
system where the modem can
transmit continuously (at a master or a
point to point system), the JP2 jumper
can be installed which will force a RTS
signal into the modem. This will cause
the modem to transmit continuously.
This will not cause a problem at a
Master Modem or in a point-to-point
system. This will not work for modems
that are connected to local controllers
that share a line going back to a
Master. The RTS pin on the edge
connector is pulled up with a 1.0K
resistor to +12V so make that nothing
is connected to the RTS pin (L).
If you are in a situation where you
don’t have control of RTS but you
have more than one modem on the
line, you will have to use a Key On
Data device to control the Modem. GDI
can supply these devices. Please
contact the factory for more
information.
A common problem in 4-wire systems
is not connecting them correctly. The
pair of wires from the Audio Out from
the Master Modem is connected to the
Audio In of all of the remote Modems.
All of the Audio Out signals from all of
the Remote Modems are connected
together and connected to the Audio
In of the Master. The Audio signals are
transformer coupled and are not
polarity sensitive.
PRELIMINARY
