Service manual

Backplane Interface Card (SMN812-313)
CARD DESCRIPTION
This card interfaces between the 2 x 37 way and 2 x 50 way 'D' sockets on the rear of the
AES960 unit, the Digital card and the 4 Daughter boards.
This card supports up to 4 daughter cards giving a maximum of 56 Input / 56 Output, AES
mono channels.
The transformers on this board support AES3 digital signals at a sample rate of 44.1khz to
96khz with at an impedance of 110 W ± 20%.
Internally the card is controlled by RS485 from the Host micro controller on the mother PCB,
this is separate to the RS485 signal on the AES960 rear panel.
Jumper LK1 to LK8 introduce digital input signal equalization when removed, these should
be fitted for normal operation with AES cables up to 100 meters.
Power for the optional MADI Optical interface is provided by 'J88'.
The external BNC word clock signal is connected to 'J91'.
The dual power supplies connect to a 'push to release' terminal block.
The external RS485 signal and the 9 pin 'D' 'PSU HEALTHY' ribbon connect to lockable 10
way IDC receptacles.
A 10 way IDC Dubox connector is fitted for in-system programming of micro controller. An 8
way IDC Dubox connector is fitted for in-system programming of PLDs only.
The board has 2 LEDs which will flash in normal operation, these are driven by a
ATmega128 micro processor (uP).
LED INTERPRETATION
D4 (green) ON indicates the card is working.
D3 (green) ON indicates communication with the
Host controller.
SW1 This is for development only, it resets the micro
controller.
Digital Service Manual
Issue 3 Page 40