4
Equinox ESP-2 OPTO Serial Hub Installation and User Guide
Table 5 lists the pin assignments for the RJ-45 shielded Ethernet connector. The 4-
wire power and 8-wire power columns apply to ESP-2 OPTO hubs that use POE;
additional information follows the table.
Table 4: Serial Port Assignments
Pin
Signal
Direction
Description
1
N/C *
N/C *
N/C *
2
DSR **
Input from TD
Data Set Ready (DSR) is driven by the remote device’s Data
Terminal Ready (DTR) signal and is used to power TxD pin 5
3
N/C *
N/C *
N/C *
4
RxD
Input from TD
Receive Data (RxD)
5
TxD
Output to TD
Transmit Data (TxD) is powered by pin 2 and/or pin 8, with pin
6 as the return
6
GND
To TD only
Signal Ground; this is an isolated return for TxD and RxD with
no connection to the hub’s logic or chassis ground
7
N/C *
N/C *
N/C *
8
CTS **
Input from TD
Clear to Send (CTS) is driven by the remote device’s Ready
to Send (RTS) signal and is used to power TxD pin 5
* Unused pins (labeled N/C) should not have wires attached to them. Floating wires could
cause unbalanced noise, shorten overall distances and degrade performance.
** DSR and CTS are required for operation, but are not seen by the hub’s CPU.
Table 5: Ethernet Connector Pin Assignments
Pin
Signal
4-Wire Power
8-Wire Power
1
Transmit Data +
+48 or -48 VDC
N/A
2
Transmit Data -
+48 or -48 VDC
N/A
3
Receive Data +
-48 or +48 VDC
N/A
4
*
N/A
+48 or -48 VDC
5
*
N/A
+48 or -48 VDC
6
Receive Data -
-48 or +48 VDC
N/A
7
*
N/A
-48 or +48 VDC
8
*
N/A
-48 or +48 VDC
* These pins are usually connected in a standard CAT 5 cable. There is special termination
for those signals in the interface to eliminate any problems if they are connected.
