Inter-Tel AXXESS Manual page 1440

Appendix B — RS232
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INTER-TEL AXXESS
1. INTRODUCTION
NOTE:
sion of RS232 is EIA/TIA-232-E (July 1991), which includes the alternate use of RTS Running
H/F 2-and CTS as character-by-character hardware flow control signals. The Inter-Tel
serial ports conform to RTS/CTS flow control per EIA/TIA-232-E. Older versions of RS232, such
as EIA-232-D (1987) and RS232-C (1969) are a subset of EIA/TIA-232-E. Hence, serial ports
which conform to EIA/TIA-232-E are compatible with all RS232-C serial ports. However, if the
RS232-C serial port does not support RTS/CTS flow control, then the connection cannot use
RTS/CTS hardware flow control.
1.1
consuming. The confusion arises because there are so many different factors that can vary on
each type of RS232 connection, such as:
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Page B-2
MANUAL VERSION 11.0 – May 2008
RS232 has undergone several revisions over the last 30 years. The most current ver-
Connecting two different devices using RS232 can be very confusing as well as time
Type of device
— DTE (Data Terminal Equipment), e.g., PC Serial COM port, Printer, etc.
— DCE (Data Circuit-Terminating Equipment), e.g., modems
Type of connector
— D-sub (a.k.a. "DB")
— Modular
Male or female gender of connector
Number of pins
— 25 pin DB
— 9 pin DB
— 8 pin modular
— 6 pin modular
— 4 pin modular
Different Cables
— 25 wire straight-through cable
— 9 wire straight-through cable
— Reversing vs. non-reversing modular line cords
— 4-wire, vs. 6-wire vs. 8-wire modular line cords
— Custom cables
— Cable length
Special Adapters
— 9-to-25 pin adapters
— "Null-modem" adapters
— Gender changers
— Custom adapters
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system
Introduction