🚀 go-pugleaf

Alan Todd (bigal@clam.rutgers.edu) wrote:

> I've recently inherited an original HP Laserjet printer. It works
> great in Self Test, but as soon as you hook up a computer to it, it
> goes off-line and flashes an error code 22. Anyone know what an error
> code 22 is?

Error code 22 is: "The serial or Centronics interface is improperly 
configured. (See App. A for interface configuration instructions.) -- 
Press 'Continue' to clear the error. Some data ay be lost. Check your 
printer interface. Parallel: the cable ay be loose. Serial: check for 
correct serial pacing option. The printer uses XON/XOFF and DTR/DSR 
signal protocols rather than the ETX/ACK protocol."

(App. A: Cable configurations.)

Which type of HP LJ exactly do you have?

> Also, there are two ports on the side of the unit: a round 9-pin
> serial (RS-232 I presume) and a 25-pin D-connector (female pins). Is
> the 25-pin connector parallel or serial? There's about 12 wires coming
> from the back of it, so I presume it's parallel, but I've seen another
> original Laserjet and it has a Centronics connector for it's parallel
> port. I get the error code when I hook a parallel line from the
> computer to the 25-pin port, but not when I hook the serial port on
> the computer to the 25-pin port. If this 25-pin connector on the
> printer is, indeed, a serial port, does anyone know what the serial
> line settings are for this machine?

I think that the 25-pin connector is serial, because HP printers usually 
have Centronics parallel port. I have documentation about the 9-pin 
serial connection:

1: RTS (1/8)
2: TxD (2/3)
3: RxD (3/2)
4: DSR (4/20)
5: GND (5/7)
6: DTR (6/6)
7: nc
8: DTR (8/5)
9: nc

(Host computer male DB9/DB25 pinouts)

The default is 9600 bauds, no parity, 8 databits, 1 stopbit.