I’d never fall for this (I hope) because our only “wired” number is through the Internet, not AT&T or any major provider.
Here’s a link to the FCC’s page: fcc.gov/guides/90-telephone-scam.
"I received a telephone call last evening from an individual identifying himself as an AT&T Service Technician (could also be Telus) who was conducting a test on the telephone lines. He stated that to complete the test I should touch nine (9), zero (0), the pound sign (#), and then hang up. Luckily, I was suspicious and refused.
Upon contacting the telephone company, I was informed that by pushing 90#, you give the requesting individual full access to your telephone line, which enables them to place long distance calls billed to your home phone number. I was further informed that this scam has been originating from many local jails/prisons. DO NOT press 90# for ANYONE…
The GTE Security Department requested that I share this information with EVERYONE I KNOW. *After checking with Verizon they also said it was true, so do not dial 90# for anyone."