--- Max <max at techbites.com> wrote:
Punching Speeds up to 75 char/sec
Reading speeds up to 400 char/sec
I would recommend a GNT 4601 or 4604, made by GN
Telematic, and also rebadged by Decitek. They meet or
For the punch, I'd recomend a Facit 4070. They're relatively common I
think, easy to maintain, and fairly simple. The basic interface is an 8
bit parallel one which can be linked to a PC with a little logic, there
was also an internal RS232/current loop card [1] and I believe I read
about an IEEE-488 card, but I've never seen one.
[1] Half of this board is taken up with instrucitons, etched into the
copper, and tinned, explaining how to set the links!
For the Reader, I like the Trend UDRs and HSRs. The interface is a little
more work, though. They're optical readers, and basically you have a
signal to start/stop the tape, 8 data outputs, and a strobe. Once you've
started the tape, you grab the data lines every time you get a strobe.
However, the thing will stop on the next character if you turn off the
tape-run line, so single-stepping is possible (although it really slows
down if you use it in this mode!). The good thing about these models is
that they're mechanicvally simple, about the only thing that ever fails
is the light bulb, and thats' a standard 12V or 24V car/lorry bulb. IIRC,
the models with intenral PSU all use a normal 382 12V, 21W car indicator
bulb, available just about anywehre over here.
The other good thing about the Trend readers is that they have 2 sensors
on the feed track, spaced 2.5 characters apart. A sproket pulse is
generated when the signal from the senosor in-line with the data holes
exceeds that from the other sensor by a particular amount, a weighted
average of the signals from the 2 sensors is then used as the threshold
for the data tracks. It's easy to set up, and works with just about any
tape you put in it.
If not,
someone suggested
interfacing it to a PC and
linking the PC to the LAN.
I have never seen a reader/punch with a direct LAN
interface. They are usually RS23C serial.
I've never seen one with a LAN (presumably ethernet) interface either.
Most of the units I have have some kind of 8 bit parallel interface
(FWIW, the Facit 4070 punch interface became a de facto standard over here).
-tony