From the beginning I thought an optional ethernet module with the ability to send email alerts (and maybe access network time servers) was an essential roZetta™ feature. I wanted a 5V device to avoid adding a 3.3V power supply and level converters for the data lines. I looked at several chip only solutions (WIZNet, ConnectOne, Microchip - too complex, too tight pin spacing, etc.), Lantronix XPort (3.3V), Digi Connect ME (too tall to fit enclosure), NetMedia SitePlayer (too limited), Moxa (too costly) and Tibbo EM202 - settling on the latter because it could operate at 5V and, while it did not do email out of the box, was programmable (in a Basic dialect) with an email example on their web site. It also had a virtual serial port driver for Linux although I found the need to rebuild the Linux kernel far too complicated, especially given the 57,000 varieties of Linux (one for nearly every Linux user) that are out there.

Unfortunately, after I had designed the roZetta™ printed circuit board to accommodate the EM202 and built an initial inventory of base units plus accessories (nearly $3000 of inventory), Tibbo discontinued the EM202 with no warning - just as I had placed an initial order with one of their dealers. They have designed a replacement but have prohibited their dealers from shipping it to the USA. I have been scrambling for another solution.

I thought to use XPort but that requires a redesign of the PCB, making current inventory obsolete and complicating support with two versions of the board in the field.

I remembered SimpleLAN which, while limited, does do email, is economical and can fit within the enclosure. It needs no design changes. The manufacturer indicated they were eager to work with me but were unwilling to add TCP and NTP. After a week of waiting for the technical details needed to write utilities to configure it under Linux and OS/X as well as hearing from a user who had a bad experience when he tried to buy one, I decided against using it.

In February 2009 both WIZNet and ConnectOne introduced new ethernet modules that are attractive for different reasons.

The WIZNET WIZ110SR is an external ethernet to serial module that does TCP and UDP which sells for $23 which is about 20% the cost of comparable modules from other manufacturers. It does not do email, it does not do NTP, it does not have a webserver. While it might be possible to implement all but the web server using TCP and UDP, these require additional ZBasic code and the memory for code is limited. But it is an economical choice if all that is needed is an ethernet interface.

The ConnectOne Nano LANReach is an internal module that does TCP, UDP, SMTP (email), NTP (Network Time Protocol), has a webserver (with embedded variables) plus much more. It sells for $38 (Mouser 890-IL-SM2144N1-I). Unfortunately, it is a 3.3V device so I have had to design a small adapter board that supplies 3.3V and does the needed level conversions for the signal lines. The adapters are on order and should be here by late April. The adapter adds $10-12 to the cost.

Neither module has virtual serial port drivers for the PC side but require TCP and UDP. That requires more coding but simplifies things across Windows, Linux and OSX.

WIZNet also has a new $42 wireless ethernet to serial adapter (WIZ610wi) which, while not practical with the current design, might have application to a future design. It is still so new that it lacks full documentation. The specifications indicate it has email capability but I need to see the final documentation to see whether it is a good fit.

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