How do I make a IBM POS VFD Customer Display work? - Help Anybody!

[Robert Wells]

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 document, 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 port 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 shipping, 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

[Sergey Kubushin]

Robert Wells <rwel...@cox.net> wrote:

Please let me know if you were able to find any information on those. I have
a hundred or so of those Futaba displays and I want to use them somehow.

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[eyez...@yahoo.com]

I doubt it is anything they don't already supply. I looked at their
site thru similar p/n's and see some that take 1200 baud with rs-232c
protocol. maybe if you (carefully) disect the unit and talk directly
to the vfd you may find joy.
regards,
al

[Robert Wells]

 

<eyez...@yahoo.com> wrote in message news:578515a7-5def-4637...@d45g2000hsc.googlegroups.com...

    Thank you for your input Al. They may use the RS-232 communication protocol but the electrical part definetly has to be RS-485. Why else would they have a rs-485 chip onboard? RS-485 support is built in on some ports of certain IBM cash registers, particularily on Port 4, the "Customer Display" port. Also the four pin cables I found for it are referred to as RS-485 in the part desc.

 

     I have done a bit more research on it and the IBM POSS (Point of Sale Subsystem) uses a driver for the VFD, VFD-DRVR.sys. In studying some of the code use to operate the display they call pos_initialize, pos_open, pos_IOCntrl, pos_write all required to operate devices. There was also a vague blurb about a function that is used to acquire the device and release it. Maybe this is an identification/ handshake with the device to verify it is a valid target before info is allowed to be displayed? I think I am going to have to find the source for this code. I'm not sure how I would go about asking IBM for this sort of information. I would bet the farm they would not release it. Hmm maybe if I signed a NDA? I don't even know where to start at IBM. Wish I had a friend there!

 

    I tried to post on the C++ moderated newsgroup to see if any POS programmers hung out there but was rejected twice for being off topic. Tried on the unmoderated C++ site and some pompous twit referred to me as being "silly" for posting there. Where the heck else could I get the attention of a POSS programmer?? More likely on a C / C++ programming newsgroup than on a electronics group I'd expect.

 

    Well the battle goes on.

 

Bob

 

[nycpar...@gmail.com]

Robert,

Do you have any updates on talking to thee displays? I came across you very old post looking for info on an IBM VFD pole display with part number 41K6814 manufactured in 2011. This is also RS 485 with Futaba PCB part number m202md08a a.

I'd like to get it talking with a standard PC. Though, I might need a USB to RS 485 or RS232 to RS485 converter.

Any info would be appreciated.

Nick

[cha...@gmail.com]

I'm going to tag on to this one as well. Hopefully Bob found something. I can throw all sorts of RS-485 at the display, but not a flicker besides the U001 post. I've read countless documents and I can't find the protocol. I have a different display but I suspect they're addresses similar.

I did not that it's interested the processor outputs a 2Hz square wave on T2 (timer2?) output that it XORs the RS-232 output from the RS-485 transceiver.

Chas, @chasxmd