Cisco Systems C819GUK9 manual Enabling the Internal Clock, Inverting the Transmit Clock Signal

Chapter 8 Configuring the Serial Interface

How to Configure Serial Interfaces

DETAILED STEPS

	Command or Action	Purpose
Step 1	nrzi-encoding	Enables NRZI encoding format.
	Example:	Enables NRZI encoding format for router.
	Router(config-if)# nrzi-encoding
	or
	Router(config-if)# nrzi-encoding [mark]

Enabling the Internal Clock

When a DTE does not return a transmit clock, use the following interface configuration command on the router to enable the internally generated clock on a serial interface:

SUMMARY STEPS

1.transmit-clock-internal

DETAILED STEPS

	Command or Action	Purpose
Step 1	transmit-clock-internal	Enables the internally generated clock on a serial
		interface.
	Example:
	Router(config-if)# transmit-clock-internal

Inverting the Transmit Clock Signal

Systems that use long cables or cables that are not transmitting the TxC signal (transmit echoed clock line, also known as TXCE or SCTE clock) can experience high error rates when operating at the higher transmission speeds. For example, if the interface on the PA-8T and PA-4T+ synchronous serial port adapters is reporting a high number of error packets, a phase shift might be the problem. Inverting the clock signal can correct this shift. To invert the clock signal, use the following commands in interface configuration mode.

SUMMARY STEPS

1.invert txclock

2.invert rxclock

	Cisco 819 Series Integrated Services Routers Software Configuration Guide
8-10	OL-23590-02