Joe,
Great response I concur, but with one caveat.
The power consumption of the Socket Modem is not very low.
Duane J. Marcroft
Telecom and Data Communications Consultant
[email protected]
At 11:49 PM -0400 4/12/01, [email protected] wrote:
In a message dated 4/11/01, Jeffrey Race writes:
What is the smallest 33.6 or 56k modem I can source
(to be embedded in a space-saving communication product)?
What about small, but not smallest, modems that are
inexpensive as well? (I am not yet certain about the
cost/size tradeoff so need multiple datapoints to
present to potential customers.)
Hi Jeffrey:
For several years Rockwell (then Conexant) produced a small module called a
Socketmodem. I believe the footprint was the same as a 40-pin dip. This
device may still be available from Conexant, but I think I read just today
that Conexant was exiting the module business, so check carefully.
Pin-compatible versions of the Socketmodem are manufactured by Multitech. I
believe that Analog Devices also sells a pin compatible version that uses
their DSP and codec.
Xecom (http://www.xecom.com) used to make modem modules, and they may still
do so.
Lastly, there is a company called Radicom (www.radi.com) that advertises
regularly in EDN. They claim to offer a large selection of modular modems.
You should be aware that in general, modem modules are primarily a
convenience solution where the buyer pays a fairly high price in exchange for
not having to design their own modem. This can be a fine solution for low
volume applications or for applications where the modem cost is not an issue.
However, for high volume and/or cost sensitive applications, it is generally
more cost effective to design your own modem using component parts. Another
advantage to designing your own modem is that you can make it more robust
than the typical modem module for things such as lightning immunity.
Modem chips or chip sets are readily available from many vendors such as
Conexant. The tricky part, though, is the design of a suitable phone line
interface circuit (sometimes called a DAA). There are many subtle design
issues to consider regarding modem performance, UL approval, CE marking, and
use in multiple countries.
If you decide to develop your own design, make sure that you get an
experienced designer. Otherwise you might waste a lot of money on failed
regulatory tests and field problems.
Joe Randolph
Telecom Design Consultant
Randolph Telecom, Inc.
781-721-2848
http://www.randolph-telecom.com
