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73M2901CE
V.22bis Single Chip Modem
APPLICATION NOTE
AN_2901CE_048 May 2009
Rev. 1.3 © 2009 Teridian Semiconductor Corporation 1
A Maxim Integrated Products Brand
Using the 73M2901CE in a Teridian K-Series Application
Introduction
The Teridian K-Series modems have been successfully implemented for many years in many low speed
data applications from Point of Sale terminals to security systems.
The Teridian 73M2901CE integrated circuit modem provides all the microprocessor control, modulation,
and demodulation functions required to implement an intelligent low speed modem. The 73M2901CE can
be thought of as a K-Series modem data pump combined with an 80C32 controller in a single integrated
circuit. All the complex handshaking, detection, and modem configuration operations can be controlled
through high-level, Hayes™ “AT” style commands, greatly reducing the code development required to
implement the modem’s functions.
This application note describes how the 73M2901CE can be used to replace the functionality of a
K-Series modem.
The 73M2901CE includes enhanced leased line modes, energy ring detection, and SMS support, among
other features. Now that all K-Series products are reaching end-of-life after 25 years of successful
production, there is need to design in replacements for them in products that are still being manufactured
and have a long lifetime remaining. There are fundamental differences in the architectures of the
K-Series and the 73M2901CE, but since the 73M2901CE can be thought of as a super-set of the
K-Series, in most cases this means hardware can be eliminated and the design simplified when going to
the 73M2901CE.
Overview
Figure 1 shows a typical standalone K-Series modem design. A dedicated controller is used for the
modem only. This dedicated controller can be eliminated since all the modem control functions are
included in the 73M2901CE modem. Additionally, the K-Series requires external op amps for the hybrid
circuit; these are integrated in the 73M2901CE.
If the K-Series design uses a controller that is shared with other product functions, the digital interfaces
are still usually simpler when using the 73M2901CE. Instead of needing to program every aspect of the
modem functions through register reads and writes to a parallel bus, the modem can be controlled
through industry standard high-level AT commands to the serial data interface that is connected to the
Host processor in the same way as the K-Series data pumps they are replacing.
