Serius/Victor 9000 printer port

With reference to my reply to Chuck's message, I've now dug out the schematics. The Sirius printer interface uses a 6522 VIA (at location U15L o nthe mainboard). Port A is bufferec by a 75160 and fet ot the data pins on the 'Centronics' connector. Port B is used for the handshake lines, in ascending bit order : DAV, EOI, REN, ATN, IFC, SRQ, NRFD, NDAC. Tese are bufferec by a 75161, always in controller mode (DC is grounds). NRFD and NDAC (o nthe 'host' side of the buffer) also go to CA1 and CA2 (respsecviely) of the VIA The 'Talk' (buffer direction) line is controlled by PB0 of the 'system VIA' at loccation U12L The pinout of the 'Centroics' socket is : DAV 1 19 Gnd D0 2 20 Gnd D1 3 21 Gnd D2 4 22 Gnd D3 5 23 Gnd D4 6 24 Gnd D5 7 25 Gnd D6 8 26 Gnd D7 9 27 Gnd NRFD 10 28 Gnd SRQ 11 29 Gnd N/C 12 30 N/C NDAC 13 31 N/C J 14 32 NDAC EOI 15 33 Gnd Gnd 16 34 REN FG 17 35 ATN NC 18 36 IFC A couple of non-obvious ones : 'J' (pin 14' is connected to ground via the jumper E26-E27 (which is not normally fitted I think). FG is frame ground (mains earth), not logic ground. I/O chips i nthe Sirius seem ot be memory mammed for some odd reason. I think the addresses are : GPIB VIA : 1110 1xxx xxx0 001x rrrr System VIA : 1110 1xxx xxx0 010x rrrr where rrrr is selexts the VIA register in the obvious order. -tony