Pin Assignments - Equinox Systems ESP-2 Product Installation Manual

Interfaces
Each port supports the standard RS-232 DTE serial signals via a male DB-9 connector, with the
exception of RI.
Each port can 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 Interface Settings on page 6.
A software configurable option lets you enable/disable a one port option. When enabled, only
port 1 is used.
When RS-485 HD signalling is set via internal jumpers, software-configurable modes can
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 set. This mode allows rapid turnaround and release of the data pair.
When RS-422 signalling is set, the receiver and transmitter are always enabled.

Pin Assignments

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