3Com CS/2500 manual Overview

1-8 CHAPTER 1: OVERVIEW

The following sections describe these connectors. Pin assignments are listed in Appendix A, “Pin Assignments. “

Serial I/O Connectors The back panel provides ten serial I/O ports, labeled J0C through J9C, using horizontally mounted 25-pin D-series subminiature female connectors (RS-232-D). All ten ports can be used to connect the server to hosts, terminal devices, or modems. The communications server acts as a data communications equipment (DCE) device and can be attached to a data terminal equipment (DTE) device, such as a terminal, host, or printer, using a straight-through cable. If you want to connect the server to a DCE device, such as a modem, use a null modem cable.

You can also have one port serve as the console port. For more information, see “Console Port” on page 1-8.

The connector numbers on the back panel correspond to port numbers used by multiprotocol communications server software (connector J0C corresponds to port 0, connector J1C to port 1, and so on).

RS-232 Interface

The default serial I/O interface for the CS/2500 series is RS-232-D. For information about pin assignments, refer to Appendix A, “Pin Assignments.”

RS-422 Interface

CS/2500 series serial ports also support RS-422 Transmit Data and Receive Data capabilities. Transmit Data lines are assigned to pins 13 and 14 of the RS-232 serial connectors, while Receive Data lines are assigned to pins 16 and 19. Pin 25 is used for automatic detection of RS-422 mode. For complete information on pin assignments, refer to Appendix A, “Pin Assignments.”

Console Port

You can configure one of the ten serial I/O ports to serve as a console port. The default is port J0. An asynchronous terminal attached to the port can be used to:

■Provide access to the server’s user interface

■Modify firmware configuration