User manual

55 000 026 – Ed. B SCOOP E-Z - User Manual 9

This document is the property of AETA and can not be duplicated without authorisation November 2001

5. Audio section

5.1. Encoding and decoding

Scoop E-Z use includes a wide range of coding algorithms. First, one can select among

algorithms compliant with ISO and ITU-T

recommendations :

? G711;

? ITU-T G722 (mono at 64 kbit/s);

? MPEG Audio Layer II at 48, 32, 24 or 16 kHz, with programmable channel

mode and bit rate ;

MPEG Audio and G722 algorithms comply with ITU-T J52 recommendation for ISDN

transmission. Besides, other algorithms are available, that are so-called “proprietary”

because they do not comply with enforced standards :

? Proprietary MPEG Layer II at 64 kbit/s or 128 kbit/s (for compatibility with

ISDN codecs that are not compliant with the J52 recommendation) ;

? 4SB ADPCM, running in mono at a 128 kbit/s bit rate; the bandwidth with this

algorithm is 15 kHz ;

? TDAC mono, running at 64 kbit/s, with a 15 kHz bandwidth ; available as an

option.

The following describes some important features of the various available algorithms and

protocols.

5.1.1. Notes about G711

G711 is the standard coding used for voice transmission on public telephone networks.

This algorithm is used for links (via ISDN) with telephones or hybrid devices.

former CCITT