It’s amazing how far you can run a telephone line. I wonder where the Central Office was.
"Mojave phone booth's number, 760-733-9969, was acquired from the CLEC by phone phreak Lucky225 on July 31, 2013 and now rings using voice over IP.[10] Callers join a conference where strangers can once again connect just like when the phone booth was active.[10] IRC over SMS was added for DEF CON 22, IRC over Signal was added for DEF CON 25 - and both are currently still working.[11][12] One can send a message via SMS or Signal with SUBSCRIBE ALIAS to 760-733-9969 to join the group chat"
I can confirm it works via Signal. No response via SMS though.