How is bisync different from async communications?
Although both bisync (binary synchronous) and async (asynchronous) are used to send data over modems, the similarity stops there. Bisync is a specific form of synchronous communications, so the real question is what is the difference between synchronous and asynchronous communications? Asynchronous communications sends each data byte individually; synchronous communications establishes a timing pattern between the transmitter and receiver and then data streams from one to the other without the overhead of start and stop bits — and usually without a parity bit — which are required by, and add overhead to, asynchronous communications. Almost all computers sold today have asynchronous communications capability. They are called by different names: COM ports, serial ports, and TTY ports. Almost no computers have built-in synchronous ports — that’s why the purchase of a synchronous communications product, like a 3780 emulator, almost always involves acquiring both hardware and software. S
