3Com Router 3031, Command Reference Manual

Page: 172 / 838

172 C
HAPTER
3: I
NTERFACE
M
ANAGEMENT
C
OMMANDS
Example
Set the CE1/PRI interface to work in E1 mode.
[3com-E1 3/0/0]using e1
Fundamental CT1/PRI
Interface
Configuration
Commands
cable Syntax
cable { long { 0db | -7.5db | -15db | -22.5db } | short { 133ft | 266ft | 399ft | 533ft |
655ft } }
undo cable
View
CT1/PRI interface view
Parameter
long: Matches a 655-feet and longer transmission line. The options for this
parameter include 0db, -7.5db, -15db and -22.5db. The attenuation parameter is
selected depending on the signal quality received at the receiving end. In this case,
no external CSU is needed.
short: Matches a transmission cable under 655 feet. The options for this
parameter include 133ft, 266ft, 399ft, 533ft and 655ft. The length parameter is
selected depending on the actual length of the transmission line.
Description
Using the cable command, you can set cable attenuation and length on a CT1/PRI
interface to match the distance of the transmission line. Using the undo cable
command, you can restore the default value
The transmission cable attenuation that the CT1/PRI interface matches defaults to
long 0db.
This command is mainly used to configure the signal waveform for transmission to
satisfy various transmitting needs. In practice, the signal quality received by the
receiving end determines whether this command will be used. If the signal quality
is relatively good, use the default setting. In this case, the CT1/PRI interface does
not need an external CSU device.
Example
Set the length of the transmission cable that the CT1/PRI interface matches to 133
feet.
[3com-T1 1/0/0] cable short 133ft