AVT MAGIC ISDN, Hardware Description

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PA G E 5 6
I N T E R F A C E S
A2.2 Audio interfaces
A2.2.1 AES/EBU interface
The AES/EBU interface is used for the transmission of digital audio and addi-
tional data.
A2.2.2 Analogue Audio interface
Remark On the analogue unit, centre-tap earthing can be set using
jumpers for the audio signals of the main audio interface. The
jumpers are indicated on the PCB. In the factory setting, there
is no centre-tap earthing.
A2.3 Network interfaces
A2.3.1 So interfaces
A2.3.2 X.21 interfaces
The MAGIC audio system has one X.21 interface available. The X.21 inter-
face allows access to transmission networks is a data interface with bit clock
(a byte clock can be used if it is provided by the network).
Socket: Digital audio interface (XLR)
Pin Signal Electrical characteristics
Input Level: V.11
,
symmetrical,
galvanically decoupled
1
GND Shield
2
RXD a Receive Data a
3
RXD b Receive Data b
Output
1
GND Shield
2
TXD a Transmit Data a
3
TXD b Transmit Data b
Socket: Analogue audio interface (XLR
Pin Signal Electrical characteristics
1
Shield Level:
Input – 6 dBu to + 12 dBu
Output – 20 dBu to + 12 dBu
Impedance:
Input >12 k
Ω
/600
Ω
Output < 20
Ω
sym.
2
Audio a In or Out
3
Audio b In or Out
Socket: 8 pole Western Socket
Pin Signal Electrical characteristics
1
not connected Recommendation: I.430
Bit rate: B Channel: 2x 64-kbit/s
D Channel: 16-bit/s
2
not connected
3
TX
4
RX
5
RX
6
TX
7
not connected
8
not connected
Push
1
2
3
Pus
h
1
2
3
1 8