Technical data

6
Systems
MAGIC DC7 XIP & XIP RM Audio Codecs
General
The MAGIC DC7 XIP systems incorporate a LAN
interface, an ISDN BRI interface and a X.21 interface. The
coding algorithms G.711 (3.1-kHz) and G.722 (7-kHz) are
implemented. For the transmission of the high quality
signals the ISDN interface, the X.21 or the LAN interface
can be used.
The compact MAGIC DC7 XIP
Audio Codec (½ x 19",
1 U) is a powerful product for mobile use as well as for
studio applications. In comparison to MAGIC DC7 XIP,
MAGIC DC7 XIP RM has a 19" design and provides an
integrated power supply.
Functionality
ISDN operating mode
Activating the ISDN interface, the MAGIC DC7 XIP
Audio Codecs can establish connections with two differ-
ent destinations. Depending on the capabilities of the
remote side, which are defined by the Service Indicator
ISDN Data or ISDN Speech, each Audio Codec works
automatically in the 3.1-kHz or in the 7-kHz mode. If
there is an incoming call, the system automatically selects
the correct 3.1-kHz or 7-kHz mode. In the 7-kHz mode
every Audio Codec can transfer a data signal in addition
to the Audio signal.
X.21 operating mode
In the X.21 operating mode the MAGIC DC7 XIP pro-
vides a coded Audio signal with data rates of 64-kbit/s
and 128-kbit/s. After selecting the Audio algorithm, the
unit measures the X.21 clock and adapts the Audio
Codec’s data rate to the X.21 line clock. Together with the
transmission of Audio signals, a J.52 data transmission
can be realised.
IP operating mode
Two IP transmission modes are available:
• Leased Line Mode with RTP
• Dial-up Mode with SIP according to the new EBU
Audio over IP standard N/ACIP TECH3326
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ISDN/LAN (SIP) Auto Mode
With the ISDN/LAN (SIP) Auto Mode the system
decides on the basis of the type of the incoming call
which network interface shall be active- ISDN or LAN/
SIP. The user in the control room can employ the ISDN/
LAN (SIP) configuration for all incoming calls. The
MAGIC DC7 XIP switches automatically to the right net-
work interface.
Interworking with Audio Codecs
In both the analogue POTS mode and the ISDN tele-
phone mode (ISDN Speech Indicator) the unit can com-
municate with all analogue, ISDN and mobile tele-
phones. In the ISDN 7-kHz mode (ISDN Data Indicator)
Audio signals with 7-kHz quality can be transmitted.
Two different synchronisation procedures are used:
• ITU-T J.52 for 7-kHz Audio & data transmission:
Using the ITU-T J.52 Recommendation a data signal
can be transferred in addition to the 7-kHz Audio
signal. In this mode the Audio signal is encoded at
48-kbit/s or at 56-kbit/s. Data signals of up to 14.4-
kbit/s can be transmitted.
• SRT for 7-kHz Audio transmissions:
If the SRT (Statistical Recovered Timing) procedure
is used, only Audio signals can be transmitted. In
this case the Audio signal is encoded at 64-kbit/s.
Each of the two Audio Codecs can use either J.52 or
SRT as its individual synchronisation mode.
In SIP mode full compatibility to VoIP
phones is provided. If the remote IP
phone also supports HD telephony with
G.722, the system will be switched auto-
matically in 7-kHz mode and offers as a
result high quality speech.
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Further details can be found under http://www.ebu-acip.org