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.