Data Communications - Data Interface Standards

Each standard defines the pinout (pin number and designation), connector type, voltage levels on each pin, and the maximum data rate and maximum distance of cable run.

This specifies a 25 pin D Type connector as a standard unbalanced (single wire signals) interface for DCE (Data Communication Equipment - Modem) or DTE (Data Termination Equipment - PC Comm Port or User Equipment).

This specifies a 25 pin D Type connector as a standard unbalanced synchronous (data and clocks) interface for DCE (Data Communication Equipment - Modem) or DTE (Data Termination Equipment - User Equipment). This interface is almost identical to RS-422 but for RS-423 is unbalanced. Very similar to RS-232 but can drive longer cable lengths at higher data rates.

This specifies a 37 pin D Type connector as a standard balanced (signal pairs) synchronous (data and clocks) interface for DCE (Data Communication Equipment - Modem) or DTE (Data Termination Equipment - User Equipment). This interface can also be on 9 way D Types and 15 way D Types.

This specifies a 25 pin D Type connector as a standard balanced (signal pairs) synchronous (data and clocks) interface for DCE (Data Communication Equipment - Modem) or DTE (Data Termination Equipment - User Equipment). This interface is identical to RS-422 but uses a 25 Way connector and is also used for RS-423 which is the same interface again but unbalanced.

This specifies a 37 pin D Type connector as a standard balanced (signal pairs) synchronous (data and clocks) interface for DCE (Data Communication Equipment - Modem) or DTE (Data Termination Equipment - User Equipment).

This specifies a 15 pin D Type connector as a standard balanced (signal pairs) synchronous (data and clocks) interface for DCE (Data Communication Equipment - Modem) or DTE (Data Termination Equipment - User Equipment). This interface has only one clock normally but the full pinout caters for two.

Next we will have a look at the pin outs...