Filter
Top Products
8-8
Cisco 819 Series Integrated Services Routers Software Configuration Guide
OL-23590-02
Chapter 8 Configuring the Serial Interface
How to Configure Serial Interfaces
Note You cannot use the physical-layer async command for frame-relay encapsulation.
Encapsulation methods are set according to the type of protocol or application you configure in the
Cisco
IOS software.
• PPP is described in Configuring Media-Independent PPP and Multilink PPP.
• The remaining encapsulation methods are defined in their respective books and chapters describing
the protocols or applications. Serial encapsulation methods are also discussed in the
Cisco IOS
Interface and Hardware Component Command Reference, under the encapsulation command.
By default, synchronous interfaces operate in full-duplex mode. To configure an SDLC interface for
half-duplex mode, use the following command in interface configuration mode.
Binary synchronous communication (Bisync) is a half-duplex protocol. Each block of transmission is
acknowledged explicitly. To avoid the problem associated with simultaneous transmission, there is an
implicit role of primary and secondary stations. The primary sends the last block again if there is no
response from the secondary within the period of block receive timeout.
To configure the serial interface for full-duplex mode, use the following command in interface
configuration mode.
Configuring PPP
To configure PPP, refer to the Configuring Media-Independent PPP and Multilink PPP.
Configuring Half-Duplex and Bisync for Synchronous Serial Port Adapters on Cisco 819 ISRs
The synchronous serial port adapters on Cisco 819 ISRs support half-duplex and Bisync. Bisync is a
character-oriented data-link layer protocol for half-duplex applications. In half-duplex mode, data is sent
one direction at a time. Direction is controlled by handshaking the Request to Send (RST) and Clear to
Send (CTS) control lines. These are described in the
“Configuring Bisync” section on page 8-8.
Configuring Bisync
To configure the Bisync feature on the synchronous serial port adapters on Cisco 819 ISRs, refer to the
Block Serial Tunneling (BSTUN) Overview. All commands listed in this section apply to the synchronous
serial port adapters on Cisco 891 ISRs. Any command syntax that specifies an interface number supports
the Cisco
891 ISRs slot/port syntax.
Command Purpose
Router(config-if)# half-duplex
Configures an SDLC interface for half-duplex mode.
Command Purpose
Router(config-if)# full-duplex
Specifies that the interface can run Bisync using switched RTS
signals.