I have four IBM POS VFD Customer Displays aka "Pole Displays" This is
the one attached to various IBM electronic cash registers that shows the
customer the price of each item as it is rung up and then the grand total.
It has two lines of twenty characters in flourescent blue or green. These
particular displays are IBM part number 61P5766. They are beautiful
displays, highly readable and from what I understand are very reliable. I
would like to be to use them in some PIC projects but there is a problem.
I
can't find information on how to make them work. They have a four pin jack
in the bottom. They have a Futaba VFD module inside and that part number
is
M202MD08A. Futaba will not give out any information as they say the design
is IBM property. This is what I've been able to figure out so far:
The suppply voltage is 12VDC on the two outer pins. Applying power
results in a display of "U001" after about three seconds. This I read in
an
IBM do***ent, indicates the initialization/self test was successful and
the
display is waiting for communications.
There is a A176B RS-485 transceiver on the display circuit board and
that is the equivalent of the TI SN75176. So I figure it must be using
RS-485 electrical communication protocol (differential pair). Thus I
figure
the two inner most pins on the connector must be the so-called AB pair
that
the signals are sent on. I have tried hooking up a LTC485 transceiver chip
to the output of my PIC 18F452 serial ****t and sent a variety of codes via
pins 2 and 3 on the display connector. I tried to display text on it,
initialize it and clear the display all to no avail. I am using a comm
setup
of 9600 baud, eight bits, no parity and 1 stop bit on the PIC. I've also
tried 2400 and 19200 baud, even parity, no luck. I am using the PIC
hserout
command. This is driving me absolutely bonkers. I don't know if I need
enable the receiver or not but I did and there was no success. What I am
wondering is if IBM has special codes in its POSS drivers that unlock this
device for communications. I guess if someone had the source to the
"customer display" section of the POSS drivers I could figure it out, but
I
can't even find any information about where such programmers hang out on
the
net. I would be most appreciative for anyone that might help. These
displays
would be great for all sorts of projects and are readable even in bright
light. With the RS-485 protocol they should be ideal for remote displays
using a twisted pair wiring at hundreds if not thousands of feet! They
have
been available from time to time on eBay for $20 US plus ****pping, brand
new
in the original IBM box! I WILL SEND ONE OF THESE UNITS TO THE PERSON THAT
CAN PROVIDE THE INFORMATION THATS GETS IT UP AND RUNNING AS LONG AS THEY
ARE
IN THE CONTINENTAL US! Please help me!
Sincerely ,
Bob
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