Difference between revisions of "IbmPosDisplay"

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Status: we can't get communication going with the display using the "simple" protocol (send 0x05 + text + \n).
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   {{Project
 
   {{Project
 
   |Name=IbmPosDisplay
 
   |Name=IbmPosDisplay
   |Status=Initializing
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   |Status=Stalled
 
   |Contact=bertrik
 
   |Contact=bertrik
 
   }}
 
   }}
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The display in question contains two rows of 20 characters each.
 
The display in question contains two rows of 20 characters each.
 
The characters on the display are of the [http://en.wikipedia.org/wiki/Vacuum_fluorescent_display VFD] type, in blue/cyan.
 
The characters on the display are of the [http://en.wikipedia.org/wiki/Vacuum_fluorescent_display VFD] type, in blue/cyan.
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The display has the following markings on its PCB:
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Futabacorp KU-02194V-O N
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On the outside it has the following markings:
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* FRU P/N 73G1105
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* P/N 73G1100
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* S/N 41-N 1 5 1 8
  
 
== Interface ==
 
== Interface ==
The electrical interface to the display consists of 4 wires, probably an RS485 interface, possibly:
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The electrical interface to the display consists of 4 wires, possibly:
 
* ground
 
* ground
 
* data A (inverting), D-
 
* data A (inverting), D-
 
* data B (non-inverting), D+
 
* data B (non-inverting), D+
 
* power (12V) - red
 
* power (12V) - red
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This is most likely an RS485 interface, because there is a 75176 (differential bus transceiver) inside the display.
  
 
A very simple RS232-to-RS485 conversion can be done by simply biasing the inverting data pin (data A) to half the supply voltage, and connecting the RS232 data line directly to the non-inverting data pin (data B).
 
A very simple RS232-to-RS485 conversion can be done by simply biasing the inverting data pin (data A) to half the supply voltage, and connecting the RS232 data line directly to the non-inverting data pin (data B).
  
 
== TODO ==
 
== TODO ==
* Are we really sure this it has an RS485 interface? (where did that idea come from?)
 
 
* Figure out baud rate
 
* Figure out baud rate
 
* Write software to control the display
 
* Write software to control the display
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Possible protocol descriptions:
 
Possible protocol descriptions:
 
* possible protocol description: [http://www-01.ibm.com/support/docview.wss?uid=pos1R1004948 SurePOS 500 Device Commands: 2x20 Customer Display]
 
* possible protocol description: [http://www-01.ibm.com/support/docview.wss?uid=pos1R1004948 SurePOS 500 Device Commands: 2x20 Customer Display]
* appendix G ("Input/Output device comma op IPnds ", page 56) of [http://www-01.ibm.com/support/docview.wss?uid=pos1R1003129&aid=1 SurePOS 500 Model XX3 Technical System Reference, version 1.3]
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* appendix G ("Input/Output device commands", page 56) of [http://www-01.ibm.com/support/docview.wss?uid=pos1R1003129&aid=1 SurePOS 500 Model XX3 Technical System Reference, version 1.3]
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* [https://www.mikrocontroller.net/topic/62831 discussion on www.mikrocontroller.net] about this display

Latest revision as of 13:36, 9 May 2014

Status: we can't get communication going with the display using the "simple" protocol (send 0x05 + text + \n).


Project IbmPosDisplay
Status Stalled
Contact bertrik
Last Update 2014-05-09

In this project, an old IBM point-of-sale (POS) display is reverse engineered to display arbitrary text. The goal of this project is not entirely clear.

The display in question contains two rows of 20 characters each. The characters on the display are of the VFD type, in blue/cyan.

The display has the following markings on its PCB: Futabacorp KU-02194V-O N

On the outside it has the following markings:

  • FRU P/N 73G1105
  • P/N 73G1100
  • S/N 41-N 1 5 1 8

Interface

The electrical interface to the display consists of 4 wires, possibly:

  • ground
  • data A (inverting), D-
  • data B (non-inverting), D+
  • power (12V) - red

This is most likely an RS485 interface, because there is a 75176 (differential bus transceiver) inside the display.

A very simple RS232-to-RS485 conversion can be done by simply biasing the inverting data pin (data A) to half the supply voltage, and connecting the RS232 data line directly to the non-inverting data pin (data B).

TODO

  • Figure out baud rate
  • Write software to control the display

External links

Possible protocol descriptions: