High-Speed Serial Interface Network Modules

Table Of Contents

Connecting Cisco HSSI Network Modules to the Network

HSSI Network Modules

Connecting HSSI Modules to the Network

HSSI Network Module LEDs

Related Documents

Obtaining Documentation, Obtaining Support, and Security Guidelines

Connecting Cisco HSSI Network Modules to the Network

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Revised: May 1, 2008, OL-12817-01

This guide describes how to connect Cisco High-Speed Serial Interface (HSSI) network modules to your network. It contains the following sections:

•HSSI Network Modules

•Connecting HSSI Modules to the Network

•HSSI Network Module LEDs

•Related Documents

•Obtaining Documentation, Obtaining Support, and Security Guidelines

HSSI Network Modules

The 1-port High-Speed Serial Interface (HSSI) network module (see Figure 1) provides connectivity for fractional DS3 rate links and slower.

Figure 1 HSSI Network Module

Connecting HSSI Modules to the Network

The HSSI module contains a 50-pin receptacle, color-coded blue. You can connect this port to a network in either of two ways:

•To an external data service unit (DSU), using a HSSI data terminal equipment (DTE) cable for operation in DTE mode (see Figure 2). The HSSI port is configured to operate in this mode by default.

•To another router for back-to-back operation, using a HSSI null modem cable. (See Figure 3.) Both routers must be at the same site. Back-to-back operation allows you to verify operation of the HSSI port or link routers directly to build a larger node. Both routers must be configured to use a 51.84-MHz internal clock.

Figure 2 Connecting the 1-Port HSSI Module to an External DSU

Figure 3 Connecting Two Routers Back to Back

HSSI Network Module LEDs

All network modules have an enable (EN) LED. The enable LED indicates that the module has passed its self-tests and is available to the router. The HSSI network module has the additional LEDs shown in Figure 4 and described in Table 1.

Figure 4 HSSI Network Module LEDs

Table 1 HSSI Network Module LEDs 

LED	Meaning
LB/C (Loopback/Connect)	Green indicates normal operation. The module is connected to the external DSU, and the signals TA (DTE available) and CA (DCE available) are active. Yellow indicates that the module is in loopback mode. If this LED is off, the port is neither connected to the DSU nor in loopback mode.
RC (Receive Clock)	Module has detected a receive clock signal. During normal operation, this signal is received from the external DSU. During loopback, it is generated internally.
RD (Receive Data)	Module has detected a receive clock signal. During normal operation, this signal is received from the external DSU. During loopback, it is generated internally.
TC (Transmit Clock)	Module is transmitting a clock signal to the external DSU. During normal operation, this signal is derived from the DSU's RT signal. During loopback, it is generated internally.
TD (Transmit Data)	Module has been detected by and can send packets to the external DSU.

Related Documents

For additional information, see the following documents and resources.

Related Topic	Document Title
Regulatory compliance and safety information	Cisco Network Modules and Interface Cards Regulatory Compliance and Safety Information http://www.cisco.com/en/US/docs/routers/access/interfaces/rcsi/IOHrcsi.html
Cisco IOS software website and reference documentation	Cisco IOS Software http://www.cisco.com/web/psa/products/index.html?c=268438303

Obtaining Documentation, Obtaining Support, and Security Guidelines

For information on obtaining documentation, obtaining support, providing documentation feedback, security guidelines, and also recommended aliases and general Cisco documents, see the monthly What's New in Cisco Product Documentation, which also lists all new and revised Cisco technical documentation, at:

http://www.cisco.com/en/US/docs/general/whatsnew/whatsnew.html

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