Impulse 2105R - Manual (Page 24)

Appendix C – Electrical Interface
RS-232
Quite possibly the most widely used communication standard is RS-232. This
implementation has been defined and revised several times and is often referred to as RS-
232 or EIA/TIA-232. The IBM PC computer defined the RS-232 port on a 9-pin D-sub
connector, and subsequently, the EIA/TIA approved this implementation as the EIA/TIA-
574 standard. This standard is defined as the 9-Position Non-Synchronous Interface
between Data Terminal Equipment and Data Circuit-Terminating Equipment Employing
Serial Binary Data Interchange. Both implementations are in widespread use and will be
referred to as RS-232 in this document. RS-232 is capable of operating at data rates up to
20K bps at distances less than 50 ft. The absolute maximum data rate may vary due to
line conditions and cable lengths. RS-232 is a single-ended or unbalanced interface,
meaning that a single electrical signal is compared to a common signal (ground) to
determine binary logic states. The RS-232 and the EIA/TIA-574 specification define two
types of interface circuits: Data Terminal Equipment (DTE) and Data Circuit-
Terminating Equipment (DCE).
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