Aethra StarVoice, Руководство по установке

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4.5 POTS and ISDN-BRI lines
4.5.1 POTS lines
POTS lines delivery high quality service and error-free connections to all analogue
telephones.
Signaling and features are as follows:
generation of low distortion unbalanced calls with high ring voltage;
⇒
⇒
⇒
⇒
⇒
no load tension
≥
40 V in idle condition;
short-circuit current higher than 22 mA with load up to 400
Ω
and higher than 18mA
with load up to 800
Ω
higher
different call patterns, including “immediate call” for CLIP, CNIP and MWI
supplementary services;
metering pulse generation.
4.5.2 ISDN-BRI lines
The ISDN-BRI lines deliver S/T interface in compliance with ETS 300 012. The S/T
interface delivers the necessary power to supply standard ISDN telephones.
ISDN level 1 activation and deactivation procedures are coordinated between StarVoice
and VAG using the ELCP Channel Allocation procedure.
Alternatively, StarVoice can be configured to keep the ISDN Level 1 with the connected
user terminal always active.
Two AAL2 channels are used for every ISDN-BRI line to supply two ISDN B channels
(B1 and B2). Another AAL2 channel is used for channel D transportation, that is to say the
channel for the transportation of ISDN signaling and services, such as X.25, frame relay.
Signaling protocols (Q.921 and Q.931) are delegated to the user-side ISDN TE and
network-side switching exchange.
The contents of B channels is normally considered as “speech”. Transparent transmission
of 64 Kbps channel bits is obtained with G.711 coding (and not SID) by deactivating the
echo cancellation function in the selected channel.
4.5.3 Audio coding - Profiles
ATMF-145000 defines different audio coding profiles.
Every profile contains one or more entries and every entry indicates a specific coding law
in addition to voice packet length.
StarVoice can be configured with one of the following profiles for every VCC assigned to
voice transportation:
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