Yes, but wasn't a key difference between the two that the early modems like the Pennywhistle, etc. were more or less totally transparent to the data stream and the connection had to be manually dialed on a separate phone's keypad, the user had to listen for an answer tone before hitting "connect", manually disconnected at the end of the call, etc. while the Hayes modem was the first popular mass-market modem which also featured the escape sequence (+++), AT commands, call progress tone detection, etc.? The latter capabilities would put all modem operations truly under program control without need for any "hands-on" manual operation or intervention.