Parallel port to 2 MB/s. Pinouts for parallel port connectors are: Inverted lines are true on logic low. If they are not inverted, then logic high is true. Pin 25 on the DB25 connector might not be connected to ground on modern computers. Hardware IC chips: Parallel port A parallel port is a type of interface found on computers (personal and otherwise) for connecting peripherals. The name refers to the way the data is sent; parallel ports send multiple bits of data at once, in parallel communication, as opposed to serial interfaces that send bits one at a time. To do this,
Serial port only through a pin header. Small-form-factor systems and laptops may omit RS-232 connector ports to conserve space, but the electronics are still there. RS-232 has been standard for so long that the circuits needed to control a serial port became very cheap and often exist on a single chip, sometimes also with circuitry for a parallel port. The individual signals on a serial port are unidirectional and when connecting two devices the outputs of one device must be connected to the inputs of the other. Devices are divided into two categories "data terminal equipment" (DTE) and "data circuit-terminating equipment" (DCE).