Product specifications

Section 3 Configuration Communication Possibilities
3BSE036351-510 A 155
• COM3 is an RJ45 port for RS-232C with modem signals. Examples of
protocols are Modbus, Siemens 3964R, COMLI or custom-design. For more
details, see protocol-specific documentation.
• COM4 is an RJ45 port for connection of service tools (see Connecting Control
Builder on page 152). The port has no modem signals.
By adding communication interfaces to the CEX-Bus, the number of protocols and
processor unit ports can be expanded. The available CEX-Bus interface quantities
are shown in Table 19 on page 156.
COM3 port is not available for PM891.