I have a old Optrex DMF6127N LCD display. I can not find any datasheets for it online (I believe it was made specially for AT&T's Bell Labs) and am trying to get it to work. I have looked at several guides on using LCDs, and they all reference Register Select and Read/Write pins. The LCD that I have, however, is missing those pins, and (supposedly) in their place are the pins FLM, LP, CP, and M.

I have found the datasheets for another LCD from Multi-Inno that can be found here. This LCD also has the same pins as my Optrex LCD, and from this I have determined that the pins are as follows:

  1. FLM: First Line Marker
  2. LP: Data latch signal
  3. CP: Clock signal for shifting data
  4. M: Alternate signal for LCD drive.

I have spent several hours now searching for how these pins work, but I still have no idea. Does anyone here know how they work? What does each one do? Does anyone have a copy of the datasheet for my LCD? (Optrex DMF6127N)

There are also pins for VSS, VCC, VEE, and pins DU0-3 and DL0-3, which I believe are standard of 8-bit LCD Character displays. (DL0-3 for 4 bit only mode?)

Thanks for your consideration!

  • 1
    \$\begingroup\$ I'm not 100% positive, but doubt that the DMF6127N is a "character module" like an HD44780. It is likely a graphics module, where FLM indicates the first line of the display, and pixel data is clocked in for each line. \$\endgroup\$
    – rdtsc
    Aug 23, 2021 at 19:09
  • 1
    \$\begingroup\$ Optrex DMF6127N may not provide detail, but NT7701 and NT7702 do. Those are on the block diagram of MI24016, page 5. \$\endgroup\$
    – jay
    Aug 23, 2021 at 19:10
  • \$\begingroup\$ it appears that the display is an LCD monitor ... it requires a video signal at the input \$\endgroup\$
    – jsotola
    Aug 23, 2021 at 19:44

1 Answer 1


The LCD you have does not have a character interface of a HD44780 controller - the point of 8-bit character displays is that provides you an 8-bit ASCII compatible interface that can be connected to a bus, and internally the controller knows how to constantly drive the rows and columns of the display with pixel data, and that's the kind of interface your display has - a direct interface for driving 4-bit pixel data directly to rows and columns, so you have to scan the display yourself.

Here's a link to similar controller : DMF-682AN


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