Specifications

AES/EBU DIO OPTION 36
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