Cisco Systems PA-4T manual Configuring Half-Duplex and Binary Synchronous Communications

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Configuring Half-Duplex and Binary Synchronous Communications

Configuring CRCs

Cyclic redundancy check (CRC) is an error-checking technique that uses a calculated numeric value to detect errors in transmitted data. All interfaces use a 16-bit CRC (CRC-CITT) by default, but also support a 32-bit CRC. The sender of a data frame calculates the frame check sequence (FCS). Before it sends a frame, the sender appends the FCS value to the message. The receiver recalculates the FCS and compares its calculation to the FCS from the sender. If there is a difference between the two calculations, the receiver assumes that a transmission error occurred and sends a request to the sender to resend the frame.

To enable 32-bit CRC on an interface, specify the slot and port address of the interface followed by the command crc 32. In the example that follows, the first serial port on a PA-4T+ in port adapter slot 1 of a Cisco 7200 series, Cisco uBR7200 series, or Cisco 7100 series router is configured for

32-bit CRC:

Router# configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

Router(config)# interface serial 1/0

Router(config-if)# crc 32

Ctrl-Z

Router#

In the example that follows, the first serial port on a PA-4T+ on a VIP2 in interface processor slot 3 is configured for 32-bit CRC:

Router# configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

Router(config)# interface serial 3/1/0

Router(config-if)# crc 32

Ctrl-Z

Router#

To disable CRC-32 and return to the default CRC-16 (CRC-CITT) setting, specify the slot and port address and use the no crc 32 command. For command descriptions, refer to the Configuration Fundamentals Configuration Guide publication. If you need more information, see the “Cisco Connection Online” section on page vii and the “Related Documentation” section on page vi.

If you are configuring a PA-4T+ installed on the Cisco 7200 series router, proceed to the following section “Configuring Half-Duplex and Binary Synchronous Communications,” otherwise, proceed to the “Checking the Configuration” section on page 8-14.

Configuring Half-Duplex and Binary Synchronous Communications

This section explains how to configure PA-4T+ interfaces for half-duplex and Bisync operation in Cisco 7100 series and Cisco 7200 series routers.

Note Cisco IOS Release 11.2(7a)P or later supports half-duplex and bisync operation on PA-4T+ port adapters in Cisco 7200 series router.

Cisco IOS Release 12.0(3)T or later, or 12.0(1)XE or later support nonstandard clock rates on

PA-4T+ interfaces installed in Cisco 7204VXR and Cisco 7206VXR routers.

8-12PA-4T+ Synchronous Serial Port Adapter Installation and Configuration

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Contents Corporate Headquarters Copyright 1997-1999 Cisco Systems, Inc All rights reserved Overview Port Adapter OverviewPA-4T Port Adapter-Faceplate View Synchronous Serial Overview Router# show diagSerial Interface Specifications Cables and Pinouts PA-4T+ Receptacles and CablesSerial Port Adapter Cables EIA/TIA-232 Connections EIA/TIA-449 Connections PA-4T+ Port Adapter Cable Pinouts EIA-530 ConnectionsRTS/CTS CTS/RTS DSR/DTR DTR/DSR RTS CTS DSR SD+ Shield ground RTS/CTS CTS/RTS DSR/DTR DTR/DSR DCD/LL Rlsd LL/DCD LEDs LEDs on the PA-4T+-Horizontal OrientationLEDs Preface ObjectivesDocument Organization Related DocumentationCisco Connection Online Documentation CD-ROM Preparing for Installation Tools and Parts RequiredSoftware and Hardware Requirements Router Platform Recommended Minimum Cisco IOS ReleaseSoftware and Hardware Requirements Safety Guidelines Safety WarningsTelephone Wiring Guidelines Electrical Equipment GuidelinesFCC Class B Compliance Preventing Electrostatic Discharge DamageFCC Class B Compliance FCC Class B Compliance Installation Overview VIP2 and the PA-4T+ Port AdapterVIP2-15 or VIP2-40 with a PA-4T+ in Port Adapter Slot Removing a Port Adapter Installing a Port Adapter Location of Port Adapter Screw-Partial Port Adapter ViewAligning a Port Adapter in a Port Adapter Slot H3152 Cisco 7206 with a PA-4T+ Installed Cisco 7200 Series PA-4T+ Port AdapterPort adapter Handle Lever unlocked Position Handling a Port Adapter Placing the Port Adapter Lever in the Locked Position-Cisco Cisco uBR7200 Series and the PA-4T+ Port Adapter Port adapters Port adapters Port adapter lever in unlocked position Inside slot guide PC board Metal carrier Placing the Port Adapter Lever in the Locked Position Installing a Port Adapter Cisco 7100 Series PA-4T+ Port Adapter Cisco 7120 Series Router-Port Adapter Slot 3 LocationCisco 7140 Series Router-Port Adapter Slot 4 Location Installing a Port Adapter Guides Installing the PA-4T+ Interface Cables Attaching PA-4T+ Port Adapter Interface CablesReplacing PA-4T+ Port Adapter Cables Incorrect, cable upside downFor a VIP2, use the following commands Router# copy running-config startup-config Configuring the PA-4T+ Interfaces Using the Exec Command InterpreterCisco 7200 Series and Cisco uBR7200 Series Ports PA-4T+ Interface Port Address Example-Cisco uBR7246 VIP2 Ports PA-4T+ Interface Port Address Example-CiscoShutting Down an Interface Cisco 7100 Series PortsEnter the shutdown command as follows Router# show interfaces serial 1/0 Performing a Basic Configuration Configure additional interfaces as requiredConfiguring Timing Clock Signals Setting the Clock RateInverting the Clock Signal Inverting the Data Signal Configuring Half-Duplex and Binary Synchronous Communications Configuring Half-Duplex Using show Commands to Verify the New Interface Status Checking the ConfigurationConfiguring Bisync Using show Commands to Display Interface Information Hardware is M4T Internet address isChecking the Configuration Router# show version VIP2 show interfaces Command Minute output rate 0 bits/sec, 0 packets/sec System image file is image-name, booted via tftp from Using ping and loopback Commands Checking the Configuration