3.2 VIDEO AND REFERENCE BOARDS
3.2.1 COHX BOARD
The COHX board is divided in 3 parts: COHX base (centre front and back), COD A
module (front left), and COD B module (front right).
COD A and COD B modules are the actual CODEC modules, each of them being
able to be configured by software either as an encoder (for a record channel) or
as a decoder (for a play channel). There are 3 hardware versions of COD modules:
SD only, HD only, or HD/SD. They are clearly identified by the sticker at the front
of the board.
There are 2 versions of the COHX base: one with genlock, one without genlock.
The genlock model can easily be identified by the presence of 3 quartz
synthesizer at the back of the board, on the right-hand side, and by the presence
of the GLK and PSU OK LEDs on either side of the DIN connector at the centre
front of the board. Note that a COHX board with genlock must
be installed as
COHX #1 in first position (slot 2) in an XT[2] system (6U or 4U). A COHX board
with genlock can never
be installed in any other slot, and thus cannot be used
instead of COHX #2 or #3. Doing so will result in conflicting electrical signals
inside the system.