The DC Hayes Micromodem II for the Apple ][ had its own weird command codes using control characters, with ^A at the "attention" command.
IN#3 (Apple ][ command to hook input from slot #3)
^A ^F (modem command to set full duplex)
^A ^Q (modem command to pulse dial the following number)
^A ^Z (modem command to hang up)
Later on once the Hayes AT command set took over and BBSs became popular in the 80's, there was a flat $25/month subscription service called "PC Pursuit" that had banks of modems in different cities connected by a network, which you could dial up locally, then connect over the network to another modem, and dial out to a local BBS system. It was a subsidiary of Telenet, which spun off from BBN, and later was a subsidiary of U.S. Sprint.
There was a fun game you could play called "PC Roulette", in which you first connected to a remote modem with the PCP command, then issued the command "A/" directly to the modem, to redial the last number somebody else dialed on that modem!
https://en.wikipedia.org/wiki/Hayes_Microcomputer_Products#E...
https://www.computerhistory.org/collections/catalog/10264598...
https://www.ebay.com/itm/393165436881
Later on once the Hayes AT command set took over and BBSs became popular in the 80's, there was a flat $25/month subscription service called "PC Pursuit" that had banks of modems in different cities connected by a network, which you could dial up locally, then connect over the network to another modem, and dial out to a local BBS system. It was a subsidiary of Telenet, which spun off from BBN, and later was a subsidiary of U.S. Sprint.
http://www.bbsdocumentary.com/library/CONCEPTS/SERVICES/PCPU...
https://bbs.fandom.com/wiki/PC_Pursuit
https://blog.tmcnet.com/blog/tom-keating/voip/pc-pursuit---t...
https://en.wikipedia.org/wiki/Telenet#PC_Pursuit
There was a fun game you could play called "PC Roulette", in which you first connected to a remote modem with the PCP command, then issued the command "A/" directly to the modem, to redial the last number somebody else dialed on that modem!