Chapter 5. Communications
192 PACSystems* RX7i, RX3i and RSTi-EP CPU Reference Manual GFK-2222AD
COM1 (RS232, RJ45 Connector)
The RJ45 Connector is provided for COM1 on CPE400
16
only. It has the following pinout.
Figure 48: COM1 Port CPE400
COM2 (RS-485, 15-pin Female D-sub Connector) –RX7i CPU/CRU Models
This port does not supply +5Vdc volts, therefore RS-485 to RS-232 conversion requires a converter that
is self-powered. It does not support the RS-485 to RS-232 adapter IC690ACC901.
This is a DCE port that allows a simple straight-through cable to connect with a standard AT-style
RS-232 port.
COM2 RS-485 Signals
Cable Shield
Located at the bottom right of the connector
as viewed from the front of the module.
Differential Request to Send A
Differential Clear To Send
Differential Receive Data A
Differential Receive Data B
Differential Request To Send B
Differential Clear To Send A
Pin 1 is the leftmost pin as shown in Figure 48.
To provide termination using the built-in 120Ω resistor, install a jumper between pins 9 and 10.
To provide termination using an external resistor, connect a user-supplied resistor across pins 10 and 11.