Configuring and Managing E1 Digital Line Cards 227
Adding an E1 Digital
Line Card
These sections tell you how to add an E1 Digital Line Card to an NBX
system:
■Preparing the NBX System for E1 Cards
■Ordering DID, CLIP, and MSN Services for E1
■Inserting the E1 Digital Line Card
Preparing the NBX System for E1 Cards
Before you insert the E1 Digital Line Card into the chassis, order an E1
line, with the specifications you want, from your telephone carrier, and
have them install the line.
Ordering DID, CLIP, and MSN Services for E1
When you order E1 with DID, CLIP, or MSN services, the local telephone
carrier assigns a block of telephone numbers to you. Usually, you can
request a specific range of numbers, but sometimes the carrier assigns
numbers other than the ones you request.
You may be able to request that the local telephone carrier pass you a
specific number of digits for each incoming telephone call. Sometimes
the carrier does not offer any choice. In either situation, you need to
know how many digits the carrier passes.
Example: Carriers commonly pass either the last three digits or last four
digits of the number for each incoming call.
Sometimes the last digits of the telephone numbers the carrier assigns to
you do not match the telephone extension numbers you want to use for
internal calls. You can create entries in your Dial Plan configuration file to
translate the incoming numbers into the corresponding extension
numbers.
Example: You want to use internal extensions from 4000 through 4999,
but the local telephone carrier assigns you numbers from 617-555-3500
through 617-555-4499. You can create translator entries in the Dial Plan
configuration file to translate an incoming digit sequence such as 3795
into extension number 4295, and a sequence such as 4213 into 4713.
The configuration would require several translator entries to handle
subsets of the total range. A unique set of entries would handle incoming
digit sequences from 3500 through 3599, from 3600 through 3699, and
each of the other sequences in which the first two digits were unique in
the range from 37XX through 44XX.