A parallel interface is faster than a serial interface because it transfers several bits concurrently. Local bus is an alternative bus that co-exists with ISA but bypasses its bottleneck. Both local bus architectures are significantly faster than the ISA bus. Type I, Type II and Type III, which are 3.3mm, 5mm and 10.5mm thick, respectively. Serial The serial port transmits data one bit at a time.
Most computers have at least one serial port.
Serial ports are most often used for the modem. Older systems sometimes use a serial port for the mouse. If you go with a serial ISDN adapter, you need to check your serial port's UART speed. The Universal Asynchronous Receiver-Transmitter is what controls the throughput on a serial port, and many PCs are equipped with 16550 UARTs, which can transfer data at a maximum speed of 115K bps. If you want to take full advantage of ISDN's 128K bps speed, you'll need a 16650 UART, which runs at 230K bps.