User's Manual

MM-5100 Hardware – User Manual

Jan. 22, 2003

15 of 18

Figure 3.3 RS-232 Interface example circuit

for Testing

MT2

(MM-5100 Wireless Modem)

RS-232 Transceiver

to TE2

(PC or PDA)

9-Pin D-SUB(femle)

DM_RXD

DM_TXD

1 DCD Data Carrier Detect

4 DTR Data Terminal Ready

8 CTS Clear To Send

3 TXD Transmit Data

7 RTS Request To Send

2 RXD Receiver Data

6 DSR Data Set Ready

9 RI Ring Indicator

15-Pin D-SUB

DCD

DTR

GND

DSR

RTS

CTS

VCC

Cable

RS-232 Transceiver

from/to

Modem

Engine

(Note 1) While the Modem is in power save mode, the MM-5100 will power itself down whenever

there is 30 seconds of inactivity on the receiver and transmitter inputs.

The MM-5100 remains powered down until an AT command is received via Host and/or has detected

an incoming call. For exiting power down state, the MODEM needs a dummy AT command to wake-

up from the power down state because the first command will be ignored.

(Note 2) ESD protection for RS-232 signal lines to +/- 15KV.

(Note 3) DM_TXD and DM_RXD signals are used for factory testing purpose.