6UC12 and 9UC12

Twelve channels of telephone quality I/O, 12 A/D and 12 D/A, interface the VME6U6 and VME9U12 boards to external analog devices, such as an operator's headset. The TDM subsystem enables the user to programmatically determine to which device (DSP, T1, etc.) each CODEC communicates.

The CODECs (Motorola MC145505) provide 8-bit companded µlaw or A-law data at an 8 kHz rate. The analog voice inputs are electrically balanced with an operating common-mode voltage range of +/-200V. The voice outputs are also electrically balanced and are able to drive up to 12Vpp into 600 ohms. Although the 9U board, 9UC12, is functionally similar to the 6U board, 6UC12, they are not interchangable. Both versions have been designed not to extend into the adjacent VME slot so that the combination of baseboard and add-on board occupies a single slot.

Gain Control
Digitally controlled gain adjustments for individual CODEC input and output amplifiers are accessible by C-callable functions. Nominal full scale input and output level is 6.3 Vpp, or 9.2 dBm referenced to 600 ohms. The input gain is adjustable from -48 to +48 dB, relative to nominal; at +48 dB gain, full scale input is 25 mVpp (-38.8 dBm). The output gain range is -42 dB to +6 dB; at +6 dB, full scale output is 12.6 Vpp (15.2 dBm).

6UC12 mezzanine board shown mounted on a VME6U6 base board.