Printer Cable

Project: Parallel cable for printing with 'Centronics' printers.
Target : C64, C128, SX64
Time   : 30 min.
Cost   : <10 US$
Use    : Print to Centronics printers without expensive interface.

Extract

Cable which connects to the C-64's user port and to the centronics jack of a printer.

Detail

Programs supporting printing are usually designed for printers connected to the serial port. But very many of them also support centronics printers (the ones for your PC) connected to the userport. For these programs (also many Speeders support centronics printers) you need the circuitry below.

For the same reason described in 'C128D keyboard for C-64' the user port must not be connected directly to the cable.

Ingredients

2-5m 11-core ribbon cable
1 user port connector
1 25-pin SUB-D connector (female) OR
1 36-pin centronics connector (male)
optionally:
74HC541
7407

Instructions

Build the following circuit on a Vector board; if you can get it, take one designed for the userport (with 12 solder pads in a 3.96mm raster)
The simple version (which requires no extra chips) is in the table below the picture.
```
User port  | 25-pin SUB-D | 36-pin centronics | Signal
-----------+--------------+-------------------+---------
 A (GND)   |    18-25     |      19-30        | GND
 B (Flag2) |     10       |       10          | /ACK
 C (D0)    |      2       |        2          | Data 0
 D (D1)    |      3       |        3          | Data 1
 E (D2)    |      4       |        4          | Data 2
 F (D3)    |      5       |        5          | Data 3
 H (D4)    |      6       |        6          | Data 4
 J (D5)    |      7       |        7          | Data 5
 K (D6)    |      8       |        8          | Data 6
 L (D7)    |      9       |        9          | Data 9
 M (PA2)   |      1       |        1          | /Strobe
```
Notes:
- Do not forget to connect pin 7 of the 7407 to GND and pin 14 to +5V.
- Pin 1, 10 and 19 of the 74HC541 must be connected to GND, pin 20 to +5V.
- For the electrolytic capacitor best use a 4.7uF tantal type, the exact value is not critical, it is only for stabilization reasons.
- For the LEDs best use a high-efficiency types, i.e. those with 2mA current consumption, else the 1.5k resistor must be 150ohms for normal LEDs.
- The 7407 pins 1, 3, 5, 9, 11 and 13 are inputs and the pins 2, 4, 6, 8, 10 and 12 are outputs! You need only 4 of the 6 drivers in the IC.
Connect the userport pins with the circuit according to the table above, on the other side of the circuit, connect either a 25-pin D-Sub plug (female, for use with standard centronics printer cables) or a 36-pin centronics plug (male).

Possible failures

Soldering errors, did you read the notes?

Updated: January 7th, 1998
Created: February 11th, 1997
Status : NOT VERIFIED!