ATDT relief
Oh man, this reminds me of a time that I got into trouble.  We had a phone system (Isotech 228, IIRC) that had these boxes call OPXIs that let standard telephone equipment connect to the phone system.  They provided talk battery and ring voltage.We had a modem tied to an OPXI, which required that our dial strings in Telit (remember that?  I liked it better than Procomm) start with "91,", which was 9 for an outside trunk, then 1 to select a trunk, then a comma for a pause.  Then the phone number of the BBS site.The OPXI messed with the newer modem speeds.  One Friday I decided that we didn't really need the OPXI if I bridged the modem with the fax line, so I did.I didn't tell anyone.  That was a mistake.Monday morning I showed up for work and my boss (the chief engineer and president) called me into his office.  Uh oh.He said, "Did you remove the OPXI from the modem line in the lab?"  "Yes."  "Why?"  "Because we didn't need it."He then told me about how he came in on Saturday, finished up some PCB artwork and went to dial into the board fabricator's BBS to upload the files (long distance), and kept getting failures to connect.  He tried it a bunch of times before he heard banging on the front door.  He went to the front and there were multiple police officers outside.  They said there were multiple 911 hangups from this location and wanted to know why.  He swore that he was the only one there and there were no 911 calls.  They then wanted to come in and look around the building, so he let them.After they left, he put it all together.  The dial strings were set up to dial 91,1-areacode-phonenumber which dialed 911 emergency without the OPXI in the path.He verified that the OPXI was no longer in the loop and was ticked off.  He knew immediately who did it.He said, "Things you do to systems other people use can have unintended consequences.  Please think those things completely through in the future."Good advice, and I still hear his voice in my head today when I'm reconfiguring something.