There are two kinds of eStim power boxes in common use today: analog
boxes and digital boxes.

Analog boxes use specially designed ‘audio’ files to create electrical
stimulation. Analog was pretty much the first way that eStim was done,
because computers were way to large and expensive to fit inside a
portable power box. Early analog was often a sort of ‘do it yourself’
deal. Many people figured out a way to use the speaker wires on an old
stereo receiver, for example.

Eventually some crude digital boxes became available, like those from
Folson, for example. These boxes are very limited in the kinds of
stimulation they generate, but they are inexpensive and many were
purchased; they can still be purchased today. In the mean time, the
Internet offered design ideas for much better analog devices and web
sites came online offering files for downloading.

Digital really came of age with the introduction of the ET-312. This
box was a huge improvement over earlier designs and quickly became the
‘gold standard’ for digital eStim. The unit features many different
wave forms and modes, is very portable, and even offers audio inputs,
although not with high fidelity.

Over the years, the ET-312 has became dated, with only two outputs,
limited ability to control over the Internet, and proprietary software.
Many people, including us at Centipede Systems wanted more.

Digital eStim boxes generate their outputs from software, and can create
many kinds of stimulation with digital precision. Using software, the
box can be updated with new features, and with ‘open software’, the box
can be improved by many contributors. We think digital eStim has lots
of advantages over analog, but there are many who will not agree with
us.

Bottom line, there is no bad choice, but there are differences, and the
more you are educated, the more likely you are to chose a system that is
best for you. But, if you can afford it, you should probably have both kinds
of boxes to play with.