Data Terminal Equipment
DTE is usually connected via an EIA-232 serial line to Data Communication Equipment (DCE), typically a modem. It is necessary to distinguish these two types of device because their connectors must be wired differently if a "straight-through" cable (pin 1 to pin 1, pin 2 to pin 2 etc.) is to be used. DTE should have a male connector and should transmit on pin three and receive on pin two. It is a curious fact that many modems are actually "DTE" according to the original standard.