V.24 Level Shifter Board

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This is a page about the v.24 level converter I made to be fully drop in replacement for the OEM board.

Features

  • Full OEM Compatibility - This will work in place of the OEM board
    • Includes a relay so that the station can originate clock _OR_ be clocked by DCE.
  • Simple design - Affordable and easy to assemble, only one IC
  • The following can be done via dip switch at the RS232 level
    • CD asserted and tied to MARK or SPACE
    • Tie TXCLK and RXCLK together - this allows a station to connect to another which is set to not send TX clock
    • Tie CTS and RTS together - needed in some cases for certain v24 to DCE connections
  • Built in cross over port to connect two stations directly without needing a crossover adapter.
  • Internally ESD (15kv) protected design - meets or exceeds the OEM v.24 daughter card or other designs based on the MC145406
  • Fits in the front or back ports of the Wireline board without contacting or putting pressure on other compntes on the wireline board.
  • Not a Graham Cracker.


Tested with TRN7477, TRN7667, CLN6955, CLN6956 and CLN7343 wireline boards.

Background info

https://www.ti.com/lit/an/slla544/slla544.pdf

https://www.analog.com/en/resources/technical-articles/fundamentals-of-rs232-serial-communications.html

https://www.analog.com/en/products/max3185.html

https://www.analog.com/media/en/technical-documentation/data-sheets/MAX3185.pdf

good:

https://electronics.stackexchange.com/a/649122

https://www.ti.com/lit/ds/symlink/tl145406.pdf