Primary Rate Interface equipment: overview
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ISDN PRI Installation
Carrier interface
The QPC720 PRI provides an interface to the DS-1 Channel either directly,
through an office repeater, or through an Echo Canceller.
The T1 Channel Service Units listed below are compatible with the QPC720
PRI card and the 64K Clear Data feature as well as with PRI connection
parameters such as the Superframe format, the Extended superframe format,
and the B7 and B8ZS Alternate Mark Inversion (AMI) line coding. See
ISDN
Primary Rate Interface description and administration
(553-2901-100) for
more information about the connection parameters.
— Digital Link 551A
— Digital Link 551C
— Digital Link 551E
— Tellabs Model 441
— Verilink Model 551V ST
In the U.S.A., FCC Part 68 regulations require Network Channel Terminating
Equipment (for example, the NT QRY551 Channel Service Unit) installed at
of the point of connection between a system and a registered common carrier
trunk.
Echo Canceller interface
Echo Cancellers are required only with satellite transmission. The Echo
Canceller detects the length of the loop, then cancels reflected transmission
(callers do not hear their own voices echoed).
The QPC720 PRI provides both a T1 line interface and a control interface to
link to a signal format compatible with EIA standard RS-232-C. Both the PRI
and the Echo Canceller act as Data Terminal Equipment (DTE). The Echo
Canceller’s control protocol must conform to that of the Tellabs Model 251.
