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17. RS-232D Serial Interface Standard |
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17. RS-232D Serial Interface Standard
The RS-232D Serial Interface Standard added the mechanical characteristics to the RS-232C Standard. The RS-232D standard defines:
- The Mechanical Characteristics of the Interface
- The Electrical Characteristics of the Interface
- The Function of Each Signal
- Subsets of the Signals for Certain Applications
The European version of RS-232D is defined in:
- V.24 - Mechanical Standard
- V.28 - Electrical Standard
Mechanical Characteristics of the RS-232D Interface defines:
- The connector is a DB25 connector. DB9 is not universally accepted.
- The connector gender is Male at the DTE and Female at the DCE.
- The assignments of signals to pins
- The maximum cable length is 50 ft.
- The maximum cable capacitance = 2500 pF. Typical cable has 50 pF/foot
capacitance.
Electrical Characteristics of the RS-232D Interface defines:
The transmitter side generates a voltage between +5 and +25 Volts for a Space (digital 0 or Low) and generates a voltage between -5 and -25 Volts for a Mark (digital 1 or High).
17a. Mechanical Characteristics of the RS-232D