Multi Tech Equipment MTA128ST - Manual (Page 44)

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Appendices
Appendix B: Ordering Your ISDN Li ne
There are two ways to specify your ISDN line configuration to your service provider. One is by using ISDN
"ordering codes" in which the user, the Local Exchange Carrier (LEC) or Internet Service Provider (ISP)
are using common nomenclature to describe elements of service. The other way of ordering service is to
use a “building block approach”; where the naming conventions are non-standardized, and the user and
provider must establish a set of provisioning options.
Loop Qualification
The first step in ordering (“provisioning”) an ISDN BRI line is to contact your LEC and verify ISDN BRI
loop availability in your location. There is a distance limitation of approximately 2 miles (1800Kf) from the
BRI loop. Each request for BRI is handled on a case-by-case basis. Once qualified, the LEC requires
information on the type of equipment and protocol used. Most ISDN BRI is configured as “voice and data” (due
to the fact that the LEC network is primarily analog, and ISDN digital technology converts the digital signal into
analog, transports it over their analog lines, and then re-converts it into digital data at the other end).
As a general procedure when ordering an ISDN BRI (2B+D) line:
1. Plan ahead; the BRI line order may take four weeks or more to get provisioned.
2. Contact your LEC representative early in the process toensure ISDN BRI loop availability for your
location.
3. Provide the LEC rep. with your correct address for the BRI service.
4. Provide the LEC rep. with the type of equipment (e.g., “Multi-Tech MTA128TA External ISDN
Terminal Adapter”) and the protocol specifications that it supports. Use the “ISDN BRI
(2B+D) Line Ordering Checklist” provided later in this document for the protocol
specifications.
5. Provide the LEC rep. with the type of jack required by the MTA128NT (i.e., “RJ45 male 2-wire U
Basic Rate Interface”).
6. Wait for notification of installation from the LEC; ask the LEC rep what type of switch is used
(AT&T 5ESS and NT DMS-100 are most prevalent).
7. Ensure availability of an “auxiliary” analog line (if you plan on using the MTA1 28NT’s “AUX”
RJ1 1 analog connector for a standard telephone connection). Make sure you have a 115
VAC (60 Hz) power outlet near your computer for the MTA1 28NT’s two-prong outlet-mounted
power transformer.
8. Record all of the information provided by your LEC.
Bearer Service
The options of Circuit Switch Voice Bearer (CSV) and Circuit Switch Data Bearer (CSD) are broad
categories of Bearer Services that the phone companies can provide. Different bearer services
provide different types of guarantees about the reliability and synchronization of the data. There are
currently ten different bearer services for circuit-mode, and three services for packet mode.
These bearer services are defined in terms of a number of attributes, which include mode (circuit or
packet), structure (bit-stream or octet-stream), transfer rate (e.g. 64Kbps), transfer capability (basically,
the content, for instance speech, 7Khz audio, video, or unrestricted), and several other attributes that
specify protocols to use and other things.
The attributes of the bearer service are encoded into a Bearer Code, or BC, that is sent everytime a
new connection is being set up. In theory, this allows the switches to dynamically choose from a
variety of different switching paths techniques depending on requirements. In practice, the
SPID is used to determine what services are needed for switching, as this greatly simplifies things for
the telephone companies. The Bearer Code will not be completely ignored, however there are
certain bearer services that will be unavailable on your B-channels, based on how they are
configured. It is important to note that the Bearer Code is sent to the switch every time a connection
is established. However, the SPID is only sent to the switch when you physically attach your