Interface from HP 9866 to the HP 1000: - 12566B-004 Line Printer Interface Kit Operating and Service Manual 12566-90019 August 1976 - bit 0 = paper loaded Paper loaded is the only status signal supplied by the printer. Paper loaded sets status bit 4. Bits 5 (online) and 6 (demand) are not set by this interface. The Tally 2000 printer generates these signals: - REDY : PRINT switch down, platen closed, paper loaded. - ON : POWER switch down, power supply up - DEMAND : printer is ready to accept data - PAPO : printer is (about to) run out of paper - FDRQ : ? - DBSY : printer is printing or slewing HP 2607 Connected to HP 12845 Interface: - bit 15 = Online (paper loaded, platen closed, PRINT button down) - bit 14 = Not Ready (power off) - bit 0 = Printer Idle For HP DVA12, Online * Idle * ~Not Ready = printer OK The printer interface connects to the 12845 via differential signals. The interface passes these signals back to the 12845: - REDY (passed via J7-S/15 as ONLINE via cable to J11-j/h to P1-26A/B to bit 15) - ON (passed via J7-T/16 as READY via cable to J11-r/s to P1-27B/A to bit 14 inverted) - REDY * -STROBE * KSTR (passed via J7-R/14 as DEMAND via cable to J11-C/D to P1-49B/A to bit 0) Tally 2000 Connected to Media III Interface: - bit 15 = Ready (power on, paper loaded, PRINT button down) [online] - bit 3 = Paper Loaded - Bit 2 = Printer Slewing [paper motion] - bit 0 = Controller Idle [data request] For ICA DVR12, Ready * Paper Loaded = printer OK The interface passes these signals back to the 12845: - REDY (passed via Jx-22/Z via cable to P2-22/Z to bit 15) - PAPO (passed via Jx-20/X via cable to P2-20/X to bit 3) - DBSY (passed inverted via Jx-21/Y via cable to P2-21/Y to bit 2) - REDY * FDRQ (passed via Jx-19/W via cable to P2-19/W to bit 0) 6, 5, 4 = idle (0), ready (15), paper out (3) LDB STATW GET THE STATUS WORD AGAIN 15 = ready ELB MOVE TO (E) CME AND BACK SIMPLY TO ERB COMPLEMENT BIT 15! 15 = not ready BRS,BRS DO WHOLE BUNCHES 15,14,13 = not ready, 1 = paper loaded, 0 = slew, lost = idle RBR,ERB OF FUNNY THINGS 15 = slew, 14,13,12 = not ready, 0 = paper loaded 14 = slew, 13,12,11 = not ready, E = paper loaded BLF,RBR JUST TO GET THE 15 = not ready, 2 = slew, 1, 0 = not ready, E = paper loaded 15, 14 = not ready, 1 = slew, 0 = not ready, E = paper loaded ELB,BLF THE STATUS BITS LINED UP 15 = not ready, 2 = slew, 1 = not ready, 0 = paper loaded 6 = slew, 5 = not ready, 4 = paper loaded CMB AND OF THE RIGHT POLARITY 6 = idle, 5 = ready, 4 = paper out Media III HP Interface ---------------------- The schematics for the HP interface show the printer cable to be driven by 7438 Quad 2-Input NAND Buffer (Open Collector) gates and received by 7404 Hex Inverter gates with 220/330-ohm voltage dividers from +5 V to ground. The I/O backplane is driven by 956 Dual 2-input CTL Buffer (Open Emitter) gates and received by 7408 Quad 2-input AND gates with 1.5K pull-downs to -2 V. The standard cable drivers and receivers have been replaced by DS8830 Dual 4-Input Differential Line Drivers and DS8820A Dual Differential Line Receivers. Driver outputs are on pins 5 (+) and 6 (-), and pins 9 (+) and 8 (-). Receiver inputs are on pins 3 (+) and 1 (-), and pins 11 (+) and 13 (-). The receiver termination resistors are connected across the differential inputs, and the strobe inputs are not connected. The PCB is constructed to accommodate either set of interface parts. To change from TTL to differential signals, 7438 TTL chips B3, C3, and D3 are removed, along with the 220/330-ohm voltage dividers and the jumpers connecting the 330-ohm resistors to ground. DS8830 driver chips are installed in locations C4, D4, C5, and D5. DS8820A receiver chips are installed in locations E4 and F4. Jumpers connecting the (-) inputs of the receivers to the corresponding outputs (and thence to the 7404 Hex Inverters) are removed. No other changes are needed. In relation to the schematic, the differential receiver (-) inputs are connected to the W, X, Y, and Z pins, while the (+) inputs are connected to the 19, 20, 21, and 22 pins. So the resulting logic levels are as shown on the schematic with the TTL inverters. (Note that the PCB labels for the A-Z and 1-22 pins are on the opposite sides of the board from the actual connections.) The differential driver (-) outputs are connected to the B-K pins, while the (+) outputs are connected to the 2-9 pins. The resulting logic levels match those with the TTL gates. Media III Tally Interface ------------------------- The PCB is constructed to accommodate either set of interface parts. To change from TTL to differential signals, 7486 TTL chip H6 and the 220/330-ohm termination resistor network A7 are removed. DS8830 driver chips are installed in locations H5 and J5. DS8820A receiver chips are installed in locations B6, C6, D6, and E6. Jumper E1 is out, enabling the bottom-of-form skip. Configuration jumpers E2 and E3 control the received polarity of the data bits and the strobe signal. E5 and E6 control the driven polarity of the status bits. All four jumpers are out, producing ground-true inputs. Jumper E4 controls auto-printing after 132 characters. The jumper is out, enabling auto-print. Jumper block J2 has pins 2-13 and 5-10. This enables printing on receipt of a LF or FF but not a CR. Jumper block J2 has pins 3-12 connected, clocking the -DCVT signal through flip-flop A3. Jumpers X1 and X2 are installed. Jumper VT-V1 is installed to select VFU1 for the top-of-form. Jumper VB-V8 is installed to select VFU8 for the bottom-of-form. Unrelated to the cabling, a modification was made to allow the printer to print control characters. The Tally interface prevents loading and printing characters from 00-37 octal. Detection is via H4-5/6, F3-6, and F4-1/2. To enable printing of all control characters except CR, LF, FF, and VT, a 7420 Dual 4-Input NAND gate was added at unused location F6. The inputs are from A3-13/12 (7400 -DCFF), H3-4 (74107 -DCVT), J4-6 (7442 -DCCR), and F3-11 (7404 -DCLF). The existing connection from H4-4 to F3-5 is severed, and the 7420 output is connected to F3-5. The character EPROM on the Buffer ROM PCB is reprogrammed to add control character glyphs matching those on the HP 2645A terminal.