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PA-8T-232 Synchronous Serial Port Adapter Installation and Configuration
OL-3562-03
Chapter 5 Configuring the PA-8T-232 Interfaces
Configuring the EIA/TIA-232 Interfaces
Setting the Clock Rate
The default operation on a PA-8T-232 DCE interface is for the DCE device to generate its own clock
signal (TxC) and send it to the remote DTE. The remote DTE device returns the clock signal to the DCE
(the PA-8T-232). Set the clock rate of an interface using the clock rate subcommand, which specifies
the clock rate as a bits-per-second value.
Before you can assign a clock rate, you must use the interface serial command (followed by the
interface address of the interface) to select the interface to which you want to assign the clock rate value.
In the following example, the clock rate is specified as 72 kbps:
Router(config-if)# clock rate 72000
The preceding command example applies to all systems in which the PA-8T-232 is supported. Use the
no clock rate command to remove the clock rate.
Following are the standard clock rates:
1200, 2400, 4800, 9600, 19200 38400, 56000, 64000,
72000, 125000 148000, 250000, 500000, 800000, 1000000,
1300000, 2000000, 4000000, 8000000
When you are done, press Ctrl-Z—hold down the Control key while you press Z—or enter end or exit
to exit configuration mode and return to the EXEC command interpreter prompt. Then write the new
configuration to NVRAM using the copy running-config startup-config command.
Note
Cisco IOS Release 11.2(7a)P or later or Release 11.1(10)CA or later loaded on your Cisco 7200 series,
Cisco 7000 series, or Cisco 7500 series router with a VIP2-40(=) supports nonstandard clock rates (any
value from 1200 to 8000000) on PA-8T-232 interfaces.
Cisco IOS Release 12.0(3)T or later or Release 12.0(1)XE or later support nonstandard clock rates on
PA-8T-232 interfaces installed in Cisco 7204VXR and Cisco 7206VXR routers.
Cisco IOS Release 11.3(7)NA or later or Release 12.0(3)T or later loaded on your Cisco uBR7200 series
router supports nonstandard clock rates (any value from 1200 to 8000000) on PA-8T-232 interfaces.
Nonstandard clock rates are rounded (if necessary) to the nearest clock rate that the hardware can
support.
Change the clock signal
back to its original phase.
no invert-txc
The example sets the transmit clock signal
for a serial interface back to its original
phase.
Router(config)# interface serial 3/0
Router(config-if)# no invert-txc
Invert the data signal.
invert data
The example inverts the data stream for
both transmit and receive for a serial
interface:
Router(config)# interface serial 3/0
Router(config-if)# invert-txc
Table 5-4
Clock Rate Configuration Commands (continued)
Purpose
Command
Example
Additional Information
