Configuring the 4-Port Serial Interface SPA
Optional Configurations
There are several standard, but optional, configurations that might be necessary to complete the configuration
of your serial SPA.
Configuring Timing Signals
All interfaces support both DTE and DCE mode, depending on the mode of the compact serial cable attached
to the port. To use a port as a DTE interface, you need only connect a DTE compact serial cable to the port.
When the system detects the DTE mode cable, it automatically uses the external timing signal. To use a port
in DCE mode, you must connect a DCE compact serial cable and set the clock speed with the clock rate
configuration command. You must also set the clock rate to perform a loopback test. This section describes
how to set the clock rate on a DCE port and, if necessary, how to invert the clock to correct a phase shift
between the data and clock signals.
Use the following commands when configuring timing signals:
Command
Router# configure terminal
Router(config)# interface serial slot/subslot/port
Router(config-if)# invert txclock
Router(config-if)# clock rate bps
Router(config-if)# invert data
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Cisco ASR 1000 Series Aggregation Services Routers SIP and SPA Software Configuration Guide, Cisco IOS XE
Optional Configurations
Purpose
Enters global configuration mode.
Selects the interface to configure and enters interface
configuration mode.
Inverts the transmit clock signal. When the
EIA/TIA-232 interface is a DTE, the invert txclock
command inverts the TxC signal the DTE receives
from the remote DCE. When the EIA/TIA-232
interface is a DCE, the invert txclock command
inverts the clock signal to the remote DTE port.
The no form of this command changes the clock
signal back to its original phase.
Set standard clock rate, in bits per second: 1200, 2400,
4800, 9600, 19200, 38400, 56000, 64000, 72000,
125000, 148000, 250000, 500000, 800000, 1000000,
1300000, 2000000, 4000000, or 8000000.
Any nonstandard clock rates that are entered are
rounded off to the nearest hardware-supported clock
rate. The actual clock rate is then displayed on the
console.
The no form of this command removes a clock rate
that has been set.
Inverts the data signal.
The no form of this command disables the inversion
of the data signal.
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