Was that one of the portable terminals with the big rubber sockets for the phone?
That was a big deal when we got one of those.
My first connectivity happened with a 103 modem that used the rubber cups for the telephone handset. It was a treasure located at a ham swap meet. Later, I found a 212 style modem at the swap meet with a direct RJ11 connection and auto-answer capability. I designed and built hardware that would use the carrier signal on the RS232 to operate a binary counter chain driven by the 60 Hz line. When the carrier detect was good, it reset the counter. The counter output operated an optically isolated AC switch. That switch remotely booted my H8 computer. That permitted me to use the H8 from the office. If carrier dropped, the counter chain started running and timed out. That dropped power to the H8. It was a fun bit of hacking in my 1981 vintage world of ham radio and computers. The counter chain had a 300 second timeout, so I could dial back into the computer if the disconnect was a transient condition.
I moved to a 2400 baud modem by 1985 and had a SLIP link to a computer at UCSD for internet connectivity. The TCP/IP stack I used at that time was from Phil Karn net/nos package. I adapted the package to run on my TRS80-Mod 16 Xenix system to run the SLIP serial protocol to the 2400 baud modem. The Xenix system also participated in the UUCP network with connectivity to multiple UNIX type systems around the world. I miss the days when e-mail wasn't loaded with SPAM. I dumped the 2400 baud modem for an ISDN 2B+D in 1987.