Pin Assignments - Equinox Systems ESP-2 MI Installation And User Manual

Each port may be configured independently to support the following interfaces:
• RS-232 DTE signaling (default)
• RS-422 signaling
• RS-485 2-wire half duplex (HD) signaling
Internal jumpers are used to select the signaling for each port. For more information,
see Changing the Physical Interface Settings on page 6.
When RS-485 HD signaling is set via internal jumpers, software-configurable modes
may be set to control the enabling/disabling of the transmitter and receiver. The
choices are RTS (Request to Send) control mode or ADDC (Automatic Data
Detection Control) mode.
• In RTS mode, the transmitter is enabled and the receiver is disabled when RTS is
true. The transmitter is disabled and the receiver is enabled when RTS is false.
• In ADDC mode, the transmitter is enabled and the receiver is disabled when a
space (zero) bit is sent. The transmitter is disabled and the receiver is enabled
when a mark (one) bit is sent. This mode allows rapid turnaround and release of
the data pair.
The RS-485 transfer mode may be specified using any of the configuration methods.
When RS-422 signaling is set, the receiver and transmitter are always enabled.

2.2 Pin Assignments

Table 3 lists the pin assignments for each port's DB-9 connector. This information is
also provided on a label on the bottom of the hub.
Table 3: Serial Port Pin Assignments
Pin
1
2
3
4
5
6
7
8
9
Not supported: RI, RS-422 RTS and CTS differential control signals.
Unused pins (labeled N/C) should not have wires attached to them. Floating wires could cause
unbalanced noise, shorten overall distances and degrade performance.
4
RS-232
DCD
RxD
TxD
DTR
GND
DSR
RTS
CTS
N/C
Equinox ESP-2 MI Serial Hub Installation and User Guide
RS-422
RXD(+)
RXD(-)
TXD(+)
TXD(-)
GND
N/C
N/C
N/C
N/C
RS-485
N/C
N/C
Data(+)
Data(-)
GND
N/C
N/C
N/C
N/C