Phil, if the age in your profile is correct I suspect you never dialed a number to which you wanted to connect your computer, listened for the modem tones, then put your phone handset into your local modem in order to make a computer connection.
You'd be entirely wrong. I used an acoustic coupler modem for the first time in 1983 (300 baud) at the age of 13. I started using modems regularly in 1987, but they were not acoustic couplers, but rather direct connection acoustic devices, starting with, at the time, a very fancy 2400 baud and over the years moving up and using a 9600 baud (briefly), then a 12000 baud (Zyxel - proprietary 12k rate, but supported standard 9600), then 14k4, 28k8, 56k, then moving away from acoustic devices on to cable modems and then ADSL. That was all personal use. In business, from the mid 90's to the early 2000's, my laptops had modems that could connect directly to the bank's computers to access various systems - done with acoustic connections, of course.
I could pick the connection speed by listening to the connection negotiation and, more than one, cancelled a call to try again to get a better connection (particularly when I was making international calls to pick up and deliver Fidonet and other FTN mail packets before I was involved in a little project that started to tunnel those packets via the internet (UUCP)) so I could do large transfers using Y-modem instead of Z-modem because Y-modem had no CRC and was therefore faster, so long as you had a clean enough line to not need the CRC (or sometimes just because I was going to be connected for a while and a cleaner connection was just plain nicer and less chance of dropping out).
That's what the term "modem" refers to: modulate and demodulate tones. We used to make data transfers with actual tones sent down the phone line.
I know. It wasn't a big mystery.
Nowadays we use a digital bridge, which sends digital signal packets down the line outside the sound bandwidth of the phone. It's always connected. You no longer have to get tonal handshaking going before you can send and receive. You even can use your telephone while the transfer is going on. We still call the box we use as a digital bridge a "modem," but it's not a modem.
Again, I know. You're referring to DSL services, they use a higher frequency. They're still called modems, as you concede.
That explain it for you? I've forgotten exactly when we stopped using modems, but I did for a long time.
Oh, I've never been in doubt as to what a modem is or what DSL is (or that when you say digital bridge you are referring to DSL services). The point, which you've missed entirely, is that if Powell was connecting or sending email via a "private line" from his laptop, he was either using an actual modem to connect to another computer or an ISP, or he was connecting via DSL using a device commonly referred to as a modem either to an ISP or to some other computer. The point is that it was a private line and not connected via the approved methods. The rest is just obfuscation on your part and a very silly attempt to suggest that only someone of your vintage would understand or be aware of acoustic (coupler or otherwise) modems and related technologies or that they wouldn't have used them.
FWIW, I was also programming Z80 processers in Assembler in 1981 and I helped to assemble my highschool's Mircobee kit computers (
https://en.wikipedia.org/wiki/MicroBee) in the mid 80's, and helping to set up the Token Ring network in the computer room where the Microbees were. That was '85 IIRC.
This is just technology that I grew up with, Russ - it's not bloody magic.
EDIT: Andrew Mentioned ISDN - yes, very fast! I never had it myself, but I had a few clients in the early 2000's with them.