AVT MAGIC AC1, Hardware & Software Manual

Page: 137 / 162

PAGE 137
T h e A u t o D y n a m i c S y n c p r o c e d u r e ( A D S )
A 2 T H E A U T O D Y N A M I C S Y N C P R O C E D U R E
The newly developed Auto Dynamic Sync (ADS) procedure allows an auto-
matic synchronisation of almost all available Audio codecs on the market.
The procedure differentiates between outgoing and incoming calls:
Outgoing call
When an outgoing call is made, the caller select the desired configuration
when he enters the calling number. In this way, the desired Audio quality, the
number of B channels and the signalling procedure is set. Since, usually the
caller knows which Audio codec he calls on the remote side, a certain Audio
transmission quality can be forced in this way. If, contrary to the expectations,
the remote side uses a non-matching procedure, the ADS automatically
searches for an ISO/MPEG frame or a G.722 signal.
ADS recognises ISO/MPEG frames with 64-kBit/s, Layer III or Layer II (if the
option is enabled), any sampling frequency (also half sampling frequencies
such as 16 kHz and 24 kHz, except 22,05 kHz and 44,1 kHz) and any mode
(Mono, Dual Channel, Stereo, Joint Stereo). Additionally, an inverted
ISO/MPEG signal is also decoded correctly.
If a G.722 signal is found instead of an ISO/MPEG frame, the synchronisation
procedures according to H.221/H.242 and SRT (Statistical Recovered Timing)
are supported.
In this way, it is ensured that at least a connection in 7-kHz quality is estab-
lished.
Incoming call
If there is an incoming call, the calling Audio codec is recognised fully auto-
matically. The procedure works with 1B channel as well as 2B channel connec-
tions. For accepting the call, you should configure the Audio codec to a mode
marked with
(AUTO)
.
TIP
Since some Audio codecs do not support different transmission parameters
in transmit and receive direction,
MAGIC DC7/AC1 provides a special func-
tion to synchronise these parameters.
To ensure that the Encoder uses the same transmission mode as the Decoder
for incoming call, you should activate the Option
Encoder follows Decoder
on incoming calls .
For outgoing calls, you can still select the transmission mode.