AES/EBU DIO OPTION
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UNIT•Y cards with AES/EBU input/output option
An 8 channel AES/EBU digital input/output option may be bought with the UNIT•Y card, or
added later on. The industry standard of digital audio transmission, AES3, normally referred
to as AES/EBU, is found on most professional audio equipment. Two channels of up to 24
bit audio is transmitted over one balanced cable. XLR type of connectors are specified.
On the AES/EBU extension of the UNIT•Y card, space has prevented us from utilizing 8
XLR connectors. Instead we have used a 25-pin SubD connector of the same type and with
the same pin assignment as on Yamaha’s single slot AES/EBU card, but the electrical
format is true AES/EBU with all inputs and outputs being transformer balanced. The robust
AES/EBU signal may be transmitted over a long distance and travel through patch-bays
etc, but the timing reference signal should be kept separately.
If you use an AES/EBU router or mechanical patch-bay, you might consider making your
own multiway cable with the terminations you need. For AES/EBU signals, relatively thin
and cheap twisted pair computer cable with a common screen is a good solution. If you use
twisted pair cable with 90-120ž impedance, the results are normally better than with more
expensive AES/EBU cable.
Remember to observe the twisting for pair identification.
Pin assignment, AES/EBU 25-pin SubD connector
Pin number
Assignment
Cable pair number
1
Input 1/2 +
1
2
Input 3/4 +
2
3
Input 5/6 +
3
4
Input 7/8 +
4
5
Output 1/2 +
5
6
Output 3/4 +
6
7
Output 5/6 +
7
8
Output 7/8 +
8
9, 11
No connection
10, 12, 13
Common
14
Input 1/2 -
1
15
Input 3/4 -
2
16
Input 5/6 -
3
17
Input 7/8 -
4
18
Output 1/2 -
5
19
Output 3/4 -
6
20
Output 5/6 -
7
21
Output 7/8 -
8
22, 23, 24
Common
25
Common
Shield
