One doesn't explain a present day claim in the past tense. (-:
In the days of the BBS boom, our cables had all of the wires, our modems did all of the signals and had lights for them on their front panels, and our operating systems either had proper interrupt-driven access to the UARTs as standard or we used things like FOSSIL. Hardware flow control was pretty much a standard feature in those times, for consumer stuff that one could buy off the shelf. Not having it did not sell, in the times when manufacturers were pushing v.42 and then v.92 in their marketing literature.
That said, a lot of the mythos about flow control has grown up because of conflation with the limits of access to a 1-byte FIFO 8250 UART on the ISA bus via MS/PC/DR-DOS. That was generally agreed to cap things at around 9600 BPS. But then along came 16550s with 16-byte FIFOs, and later still southbridges and hardware that just pretended that an ISA bus even existed. And OS/2 and Windows NT. Along with all of the vendors who were selling ISA or PCI internal modems.
It really never was the case that there was one fixed bit-rate that was "the fastest" above which suddenly everything changed. And nowadays the UARTs that modern PC users have (the internal ones usually secretly still being there in the chipsets) are devices on what is at minimum (and almost never) a "low" speed 1.5Mb/s version 1.0 USB. The aforementioned FT232R has 256-byte transmit and 128-byte receive FIFOs, and its datasheet claims up to 3M BPS.
Stating a serial port speed limit from roughly 1989 in 2025 is quite bizarre to those of us who lived through the BBS boom. It must have arrived in a DeLorean driven by some bloke named Marty.
In the days of the BBS boom, our cables had all of the wires, our modems did all of the signals and had lights for them on their front panels, and our operating systems either had proper interrupt-driven access to the UARTs as standard or we used things like FOSSIL. Hardware flow control was pretty much a standard feature in those times, for consumer stuff that one could buy off the shelf. Not having it did not sell, in the times when manufacturers were pushing v.42 and then v.92 in their marketing literature.
If you are saying that now people have to worry about not having hardware flow control again, then that's further demonstration of how things have regressed. Serial cables with only 4 wires used to be something that was passé.
That said, a lot of the mythos about flow control has grown up because of conflation with the limits of access to a 1-byte FIFO 8250 UART on the ISA bus via MS/PC/DR-DOS. That was generally agreed to cap things at around 9600 BPS. But then along came 16550s with 16-byte FIFOs, and later still southbridges and hardware that just pretended that an ISA bus even existed. And OS/2 and Windows NT. Along with all of the vendors who were selling ISA or PCI internal modems.
It really never was the case that there was one fixed bit-rate that was "the fastest" above which suddenly everything changed. And nowadays the UARTs that modern PC users have (the internal ones usually secretly still being there in the chipsets) are devices on what is at minimum (and almost never) a "low" speed 1.5Mb/s version 1.0 USB. The aforementioned FT232R has 256-byte transmit and 128-byte receive FIFOs, and its datasheet claims up to 3M BPS.
Stating a serial port speed limit from roughly 1989 in 2025 is quite bizarre to those of us who lived through the BBS boom. It must have arrived in a DeLorean driven by some bloke named Marty.