Appendix Hrs232C Interface Specifications - Multitech MT2834MR Owner's Manual

PN 88300150
The MT2834MR's RS232C interface circuits have been designed to meet the electrical specifications
given in EIA (Electronic Industries Association) RS232C standards. 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:
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:
Binary State One
Timing FunctionOff
The input impedances of all modem circuits which accept signals from the data processing terminal or CPU equipment have
DC resistances of 4.7K. For more specific details, consult the EIA RS232C standard itself.
The following chart lists the EIA RS232C interface pins and circuits present on the MT2834MR's RS232C
Interface connector. All other pins are unused.
PIN MULTI-TECH
CIRCUIT FUNCTION
1 PG
2 SD
3 RD
4 RTS
5 CTS
6 DSR
7 SG
8 CD
9 +V
12 HS
15 TC
17 RC
20 TR
22 RI
24 XTC
25 OOS
* 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
RS232C standard.
4/3/01
Appendix H
RS232C Interface Specifications
NEGATIVE
Zero Signal Condition
On
EIA SIGNAL
— —
BA DTE
BB DCE
CA DTE
CB DCE
CC DCE
AB —
CF DCE
+V DCE
-- DCE
DB DCE
DD DCE
CD DTE
CE DCE
DA DTE
CN DTE
POSITIVE
Mark
ASSIGNMENT DESIGNATION
Protective Ground
Transmitted Data
Received Data
Request to Send
Clear to Send
Data Set Ready
Signal Ground
Data Carrier Detector
Test Voltage
High Speed
Transmit Clock
Receive Clock
Data Terminal Ready
Ring Indicator
External Transmit Clock
Terminal Busy
Space Control and
CIRCUIT SOURCE*
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