Specifications

Serial Interface Configuration Examples

IC-116

Cisco IOS Interface Configuration Guide

In synchronous mode, low-speed serial interfaces support all interface conﬁguration commands

available for high-speed serial interfaces, except the following two commands:

• sdlc cts-delay

• sdlc rts-timeout

When placed in asynchronous mode, low-speed serial interfaces support all commands available for

standard asynchronous interfaces. The default is synchronous mode.

Note When you use this command, it does not appear in the output of show running conﬁg and

show startup conﬁg command, because the command is a physical-layer command.

Return a Low-Speed Serial Interface to Synchronous Mode

To return to the default mode (synchronous) of a low-speed serial interface on a Cisco 2520 through

Cisco 2523 router, use the following command in interface conﬁguration mode:

Serial Interface Conﬁguration Examples

This section includes the following example groups:

• Enable Interface Conﬁguration Examples

• HSSI Conﬁguration Examples

• Channelized T3 Interface Processor Conﬁguration Examples

• PA-E3 Serial Port Adapter Conﬁguration Example

• PA-T3 and PA-2T3 Conﬁguration Example

• Packet OC-3 Interface Conﬁguration Examples

• APS Conﬁguration Examples

• CSU/DSU Service Module Examples

• Low-Speed Serial Interface Examples

Enable Interface Conﬁguration Examples

The following example illustrates how to begin interface conﬁguration on a serial interface. It

assigns Point-to-Point (PPP) encapsulation to serial interface 0.

interface serial 0

encapsulation ppp

The same example on a Cisco 7500 series routers requires the following commands:

interface serial 1/0

encapsulation ppp

Command Purpose

no physical-layer Return the interface to its default mode, which is

synchronous.