This article discusses the concept of "realtime enough" by way of an example, a realtime 1200 baud Bell-202 FSK modem for Caller ID, implemented under FreeBSD 5.3
As chips get faster and faster, the requirement to use a conventional "Real Time OS" (RTOS) decreases, simply due to the fact that non-RTOS (and indeed, even free) systems are "fast enough" to handle the data processing requirements.
By way of example, the caller ID FSK 1200 baud modem used to be implemented in hardware, typically as a module that would accept tip and ring from the phone line on one end, and produce RS-232 on the other end.
This article shows a software-only implementation of this, running on a "non realtime" free operating system.
