Multi-Tech Systems MT2834MR6 manual Appendix F, RS-232C Interface Specifications

Appendix

Appendix F

RS-232C Interface Specifications

The MT2834MR6’s serial interface circuits have been designed to meet the electrical specifications in EIA (Electronic Industries Association) Recommended Standard 232, Revision C (RS-232C). All signals generated by the modem are approximately 10 volts when measured across a load of 3000 ohms or greater. The receiving circuits of the modem accepts signals in the 3 to 25 volt range. The voltage thresholds are defined as follows:

Negative: voltage more negative than 3 volts with respect to signal ground

Positive: voltage more positive than +3 volts with respect to signal ground

Signal Information	Negative	Positive
Binary State	One	Zero
Signal Condition	Mark	Space
Control and Timing Function	Off	On

The input impedances of all modem circuits that accept signals from the data processing terminal or CPU equipment are 4.7KW. For more specific details, consult the EIA RS-232C standard. The following chart lists the EIA RS-232C interface pins and circuits present on the MT2834MR6’s RS-232C serial interface connector. All other pins are unused.

Pin	Multi-Tech	EIA	Signal
Assignment	Designation	Circuit	Source*	Circuit Function
1	PG	—	—	Protective Ground
2	TD	BA	DTE	Transmitted Data
3	RD	BB	DCE	Received Data
4	RTS	CA	DTE	Request to Send
5	CTS	CB	DCE	Clear to Send
6	DSR	CC	DCE	Data Set Ready
7	SG	AB	—	Signal Ground
8	CD	CF	DCE	Data Carrier Detector
9	+V	+V	DCE	Test Voltage
12	HS	--	DCE	High Speed
15	TC	DB	DCE	Transmit Clock
17	RC	DD	DCE	Receive Clock
20	TR	CD	DTE	Data Terminal Ready
22	RI	CE	DCE	Ring Indicator
24	XTC	DA	DTE	External Transmit Clock
25	OOS	CN	DTE	Terminal Busy

*DTE = Data Terminal Equipment (terminal or computer) DCE = Data Communications Equipment (the modem)

The computer or terminal should be supplied with a cable terminated with a Cinch DB25P or equivalent connector mounted in a Cinch DB51226-1 or equivalent hood assembly as specified by the EIA RS-232C standard.

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