[net.micro.pc] Epson MX-80 vs. Sperry IT

dhp@ihnp3.UUCP (Douglas H. Price) (11/28/85)

Well, I've tried a number of things, and I'm stumped.  I have two-year-old
Epson MX-80 with Graftrax, and I can't get it to talk properly with
a new Sperry IT (an AT clone) that I recently purchased.  The cable was
a 'standard' IBM parallel interface cable purchased at Computerland (I felt
lazy that day about building a new cable.)  Configuration:

	Sperry IT 8Mhz 80286
	1 Meg Memory
	1 Ports card, 2 serial, 1 parallel port
	1 Persyst mono card with configurable parallel port

	MS-DOS 3.1
	SCO Xenix-286 System Vr2 (1315 dhrystones!)

The motherboard and the ports card are made by Mitsubishi.  The ports card
is hard-wired to be LPT1:  We needed to add the Persyst mono card to permit
reconfiguration of its parallel interface to LPT2:.

The printer/cable combination works under MS-DOS 2.1 and Xenix 3.0 on a 
regular 8086 Compaq.

Symptoms: Under Xenix, a reboot of the machine causes a reset on the printer,
so that much is working.  When plugged into the LPT1 port, the ready lite
goes out on the printer.  It stays on when plugged into the LPT2 port.
Nothing will print on the LPT1 port.  In fact, catting a file the LPT1
port will hang the console, requiring a reboot.

On the LPT2 port (the mono card), the printer runs VERY slowly.  It looks
like characters are being delivered to the printer at about 110 baud, and the
printer wakes up once and a while and prints out a line.  

Plugging in another printer/cable combination works without a hitch.  I haven't
yet tried swapping cables and printers, since they are in two different 
places and are inconvenient to bring together.

I thought I would just ask the world if there is anything funky about the
AT interface, or whether Mitsubishi has done something odd.  Opinions?

-- 
						Douglas H. Price
						Analysts International Corp.
						@ AT&T Bell Laboratories
						..!ihnp4!ihnp3!dhp