Avocent ESP-4 MI User Manual

6 ESP-4 MI Serial Hub Installer/User Guide
Adaptors
Two adaptors are available from Avocent to enable use of standard CAT 5 cable twisted pairs for
RS-422 receive and transmit signals, plus one of the pairs for the RS-485 signal pair.
Table 2.4 lists the pin assignments for the RS-422 CAT 5 adaptor.
4 TxD (-) Transmit Data (neg) Output
5 GND Ground N/A
6 DSR (RS-232) Data Set Ready (remains RS-232) Input
7 RTS * (RS-232) Request to Send (remains RS-232) * Output
8 CTS * (RS-232) Clear to Send (remains RS-232) * Input
9 N/C N/A N/A
* The RS-485 interface is implemented by using special cables that connect RxD(+) to TxD(+) and RxD(-) to
TxD(-), thus providing the 2-wire bidirectional interface. In addition, pins 7 and 8 should be jumpered together
to signal that the port is configured for RS-485. Pins 7 and 8 should be left open for an RS-422 configuration.
Table 2.3: RS-422 and RS-485 Serial Port Pin Assignments (Continued)
Pin Number RS-422/485 * Description Direction
Table 2.4: RS-422 CAT 5 Adaptor Pin Assignments
Pin Number - DB-9 RS-422 Description Pin Number - RJ-45
1 RxD (+) Receive Data (pos) 1
2 RxD (-) Receive Data (neg) 2
3 TxD (+) Transmit Data (pos) 4
4 TxD (-) Transmit Data (neg) 5
5 GND Ground N/C
6 DSR (RS-232) Data Set Ready N/C
7 RTS (RS-232) Request to Send N/C
8 CTS (RS-232) Clear to Send N/C
9 N/C N/A N/C

Avocent ESP-4 MI Specifications

General

Brand	Avocent
Model	ESP-4 MI
Category	Switch
Language	English