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I am able to find several commercial ICs for converting CMOS or TTL input levels translate to RS-422 output levels. (I.e One 5V single input to two differential output). However, I couldn’t find how to make it vice versa. From a pair of signals comes out with RS-422 to one single). Any idea how can I?

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Those are called RS-422 receivers. If you can't find a separate receiver, use a transceiver in receive mode.

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  • \$\begingroup\$ Thanks a lot, appreciated. \$\endgroup\$
    – Xant
    Commented Sep 19, 2023 at 9:08
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You should probably start your search at the classic SO8 of the "MAX485" variety, for which plenty of second source options are available. This one is a single channel transceiver, meaning it can handle one single channel either as Rx or Tx but not both at once.

Most often you want both a Rx and a Tx though, in which case the best option is to use 2x MAX485. One transceiver set as Rx and one as Tx. With both listening to the same differential signal you can get RS-485 semi-duplex, or on two different differential signals for RS-422 full duplex.

Lots of more advanced parts are available, with multiple channels, built-in isolation and so on. But these aren't typically well-standardized and therefore require you to enter yet another abusive marriage with the favorite semiconductor vendor of your choice...

By default these are 5V logic but 3.3V options are also common, with same pin-out just different part numbers.

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