V.24 Level Shifter Board

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.

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