Multitech MultiModem II MT5600BA-V92-NAM User Manual page 51

RS-232 Pin Descriptions
Label
CGND
TD
RD
RTS
CTS
DSR
GND
CFLO
+12V
TCLK
RCLK
V54-2
DTR
RDL
RI
XCLK
TM
Multi-Tech Systems, Inc. MT5600BA-V92 User Guide
Downloaded from Elcodis.com electronic components distributor
Appendix D - Pin Descriptions
Pin I/O Type Signal Name/Description
1 GND CGND is tied common to GND on the modem's PCB.
2 Transmitted Data The DTE uses the TD line to send data to the
modem for transmission over the telephone line or to transmit
commands to the modem.
3 Received Data The modem uses the RD line to send data received
from the telephone line to the DTE and to send modem responses to
the DTE.
4 Request to Send The RTS signal is used for hardware flow control.
5 Clear To Send CTS is controlled by the modem to indicate whether or
not the modem is ready to transmit data. CTS high indicates to the DTE that
signals presented on TD will be transmitted to the telephone line.
CTS low indicates to the DTE that it should not transfer data across
the interface on TD.
6 Out Data Set Ready DSR indicates modem status to the DTE. DSR low
indicates that the DTE is to disregard all signals appearing on the
interchange circuits except Ring Indicator (RI). It reflects the status of
the local data set, and does not indicate an actual link with any
remote data equipment.
7 GND Ground.
8 CD Carrier Detect The modem uses the CD line to signal to the DTE
that a carrier has been detected.
9 A positive voltage output from the modem used for tests or for
strapping signals high if needed.
10 NC
11 NC
12 NC
13 NC
14 NC
15 TC Transmit Clock Output from modem, used in synchronous mode.
16 NC
17 RC Receive Clock Output from modem, used in synchronous mode.
18 AL Analog Loop Input to modem to enable analog loop test.
19 NC
20 DTR Data Terminal Ready Input to modem from DTE to control
answering and disconnection of modem.
21 RDL Remote Digital Loop Input to modem to enable RDL test.
22 Ring Indicator RI output high indicates the presence of a ring signal
on the telephone line.
23 NC
24 XCLK External Clock Input to modem used in special synchronous
applications.
25 TM Test Mode Output from modem to indicate modem is in one of the
test modes.
Appendix D – Pin Descriptions
51