Multi-Tech Systems Modem Module MT3334SMI - Manual (Page 12)

ModemModule Developer’s Guide
MT3334SMI 12
MT3334SMI Pin-out
The MT3334SMI uses a 20-pin interface to provide an on-board DAA with tip and ring connections,
audio circuit for call-progress monitoring, LED driver for call status annunciation, and serial interface
via TTL level signals.
-RESET
DGND
DCDIND
RXIND
DTRIND
TXIND
24
26
29
30
31
32
DLED
SPKR
AGND
VCC
Audio
64
63
61
DGND
-DTRTTL
-DCDTTL
-CTSTTL
-DSRTTL
-RITTL
-TXDTTL
-RXDTTL
-RTSTTL
41
40
39
38
37
36
35
34
33
Serial TTL
DAA
Tip
Ring
1
2
Figure 1-5. MT3334SMI Pinout