ProSoft Technology PTQ-101M - Manual (Page 151)

Reference PTQ-101M ♦ Quantum Platform
IEC 60870-5-101 Master Communication Module
ProSoft Technology, Inc. Page 151 of 181
May 14, 2008
RS-232: Null Modem Connection (No Hardware Handshaking)
This type of connection can be used to connect the module to a computer or field
device communication port.
Note: If the port is configured with the "Use CTS Line" set to 'Y', then a jumper is required between
the RTS and the CTS line on the module connection.
7.4.3 RS-485
The RS-485 interface requires a single two or three wire cable. The Common
connection is optional and dependent on the RS-485 network. The cable required
for this interface is shown below:
Note: Terminating resistors are generally not required on the RS-485 network, unless you are
experiencing communication problems that can be attributed to signal echoes or reflections. In this
case, install a 120 ohm terminating resistor on the RS-485 line.