APPENDIX D
CELP CIRCUIT VOICE LEVEL TESTING
INTRODUCTION
The CELP (Codebook Excited Linear Predictive) module is installed and
used in General DataComm multiplexer equipment to provide several
different types of application scenarios. These scenarios range from the
simplest (4-wire) applications to the most complex applications using con-
ference networks with analog bridging of tandem CELP circuits.
This appendix requires that you have some familiarity with voice
telephony. In order to make full use of the procedures and guidelines you
may need to refer to other references. One recommended reference which
provides general background information is
a 3 volume set entitled:
Telecommunications Transmission Engineering
ISBN Number 1-878108-04-2
published by:
The Bell System Center for Technical Education
USA Phone Number (201) 699-5802
You should be able to identify the features used by the equipment being
connected to the voice module. This information is available from the
vendor in the form of technical manuals. In the case where it is not
available it is necessary to formulate the operating characteristics of the
connected equipment. This appendix provides a relatively simple
procedure to identify these characteristics.
The contents are arranged into three main sections:
GENERAL COMMENTS
OUTLINES OF PROCEDURES
DETAILED PROCEDURES
The CELP installer should read the General section, and then select the
appropriate installation procedures for each situation. Note that the first
and second sections are outlines of the main procedures and terminology
and do not include all of the details. The third section is used to describe
the procedures in full detail.
You are also required to use the manuals provided with the test equipment
to select the correct options to run each test.
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