Serial Ports
● SYSCON Debug – This serial RS-232 port provides the SYSCON2.1 debug function on
the CAC3. The debug port has no support for hardware handshake. The debug port is
accessed via a DB9 connector on the front of the SYSCON assembly cage.
● Serial Ports 1 and 2 – The SYSCON2.1 is equipped with two serial ports, each ground-
isolated and configurable for RS-232 or RS-485. Both ports support RTS/CTS hardware
handshake. Maximum supported data rate on the serial ports is 115200 bits/second. Serial
Port 1 supports Modbus and Serial Port 2 may be used to support a printer.
Note
RS-485 Operation
When configured for RS-485 operation, the serial ports are designed to comply with the
Profibus standard. This results in a different pinout than for the previous version of SYSCON
(pins 8 and 2 reversed). For backward Modbus RS-485 compatibility when replacing a
with a SYSCON2.1, an adapter cable (part number A5E02283873001) is
available.
DB-9 Pin
RS-232 Signal
RS-485 Modbus Signal
1
-
-
2
RX
%v power
3
TX
Line B (RxD+/TxD+)
4
-
-
5
GND
Common
6
-
-
7
RTS
-
8
CTS
Line A (RxD-/TxD-)
9
-
-
● Serial Ports 3 and 4 – These two serial ports, equipped on the same slot connector as the
SYSCON Debug port, are not active in software release 5.0.
I
2
C Bus
The I
2
C connectors are shown in the upper right corner of the
SYSCON2.1 Connections
photo.
Two I
2
C buses are equipped on the SYSCON2.1. These are labeled I
2
C Bus A and I
2
C Bus B.
● I
2
C Bus A includes the two connectors on the right as shown in the
SYSCON2.1
Connections
photo. I
2
C Bus A is dedicated and hard wired to the CAN Bridge function. This
allows the new SYSCON2.1 to interface with legacy CAN I/O cards in the PCI slots.
● I
2
C Bus B includes the three I
2
C connectors on the left as shown in the
SYSCON2.1
Connections
photo. I
2
C Bus B is supports2 future configuration changes in the Maxum II.
Electronic Compartment Component Descriptions and Maintenance Procedures
2.3 System Controller Version 2.1 (SYSCON2.1)
Maxum II Reference Manual
42
Manual, 7/2017, 2000596-001