Here is a guess (for what it is worth)! 1X1T1 seems to be referring to a single channel output or possibly an opto isolated high and low connection.
It really takes more context to make a useful suggestion.
Giving details such as what pins of a certain device those relate to actually will get you some better answers.
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A great troubleshooting tip...."When you eliminate the impossible, whatever remains, however improbable, must be the truth." Sir Arthur Conan Doyle