Serial Pin Configurations - Multitech SocketModem MT5600SMI-32 Developer's Manual

Serial Pin Configurations

The serial interface use an 16-pin interface to provide an on-board DAA with tip and ring connections,
audio circuit for call-progress monitoring and serial interface via logic level signals.
Pin Signal
# Name
1 Tip I/O
2 Ring I/O
24 –RESET I
26 DGND
29 DCDIND
30 RXIND
Multi-Tech Systems, Inc. SocketModem MT5600SMI Developer's Guide
Figure 2–2. Serial SocketModems Pins
Available with or without LED Pins
Pin Descriptions for Serial SocketModem Devices
I/O
Description
Type
Tip Signal from Telco. Tip connection to the phone line (RJ11 Pin 3).
SocketModem is Tip/Ring is polarity insensitive.
Ring Signal from Telco. Ring connection to the phone line (RJ11 Pin 4).
SocketModem is Tip/Ring is polarity insensitive.
Modem Reset (with weak pull-up). The active low –RESET input resets the
SocketModem logic and returns the AT command set to the original factory
default values or to "stored values" in NVRAM. –RESET is tied to VCC
through a 400ms time constant circuit for "Power-on-Reset" functionality. The
modem is ready to accept commands within 6.5 seconds of power-on or reset.
Reset must be asserted for a minimum of 300 ns.
Ground
DCD LED. Output from 74AC05 with 1500 Ohms pull-up.
RX LED. Output from 74AC05 with 1500 Ohms pull-up.
Chapter 2 – Mechanical Specifications
9