[ct-user] CT-MFJ 434

[Bob Schreibmaier]

Good information, Pete.  I had not really thought
about that.  My impression was the LPT port had
ground on pins 18 through 25.  I saw pins 11 and
25 in the manual and just hooked it up that way.

After the contest (of course) and "just for grins,"
I tried to run my interface box using CTWin 10.02.03,
NA 10.59 in a DOS window on Windoze 98SE, and CT-DOS
9.87, also in a DOS window.  NA and CT-DOS keyed
fine, although I still need to determine from where
the hum is coming.  CTWin didn't key it at all.
Backtracked to CTWin 9.92.01 -- it also didn't key
the interface at all.

LPT port set to ECP, if that matters.

73,
Bob

 >The LPT "standard" function for pin 11 is a busy flag from the printer to
 >the computer.  When the printer asserts a logic one on this pin, the 
normal
 >LPT response is to stop sending data to the printer until the busy 
flag is
 >set low by the printer.  It is a handshake pin indicating the status of a
 >print buffer in the printer.  So the electrical interface in most 
computers
 >is configured as a logic input.  It cannot be used as ground.  Pin 18 is
 >the ground pin on the 25 pin LPT connector.  The pin numbers above 18 are
 >usually ground also, but some manufacturers may not have made all the
connections.

-- 
+----------------------------------------------+
| Bob Schreibmaier K3PH | E-mail: k3ph at ptd.net |
| Kresgeville, PA 18333 | http://www.dxis.org  |
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