I’d like to share a little bit about what I learned in case it may help someone else and also Id like to get some input from others who have gone with Magic Jack in their setup.
Because if it’s one thing that stumped me in the beginning of this project it was this line voltage business.
In doing my research about connecting DreamPi I found this forum (thanks to all) and I found a thread one thread in particular that helped me immensely:
viewtopic.php?t=10773
It’s a discussion on how the Magic Jack can be used to induce line voltage in the DreamPi setup. It’s a very convenient workaround to the line voltage issue. But there is a catch: you must get the correct model Magic Jack.
What makes it the correct model? Whether it puts out normal or reverse polarity. A key source of information on polarity and how it relates to Magic Jack is cited- Sandman’s Magic Jack Bulletin:
https://www.sandman.com/knowledgebase/m ... h-bulletin
Sandman tests 7 different versions of Magic Jack to determine the polarity on the connection with each device. His findings are that 4 of those models put out the correct (normal) polarity and 3 of those models put out the incorrect (reverse) polarity.
More specifically, these are the device’s with polarity output that tested normal:
-Magic Jack 1(v1)
-Magic Jack 1(v2)
-Magic Jack Plus (v1)
-Magic Jack Go
And these are the devices with polarity output that tested as reversed:
-Magic Jack 1(v3)
-Magic Jack 1(v4)
-Magic Jack Plus (tv2)
So, the assumption is that one must have a Magic Jack on the “good list” in order for proper line voltage to be induced.
I ended up with a Magic Jack on the “bad list” by accident. My Magic Jack was putting out reverse polarity.
But it was all good because there was an easy fix: reverse RJ11 cord. When I hooked up my supposedly incorrect model Magic Jack with a reverse RJ11 instead of a straight RJ11 the result was that I was able to connect.
RJ11 Phone cords are manufactured with wires in either “reverse” and “straight” configurations because analog phone systems pre 1970s/1980s were wired with polarity in mind. Nowadays, on the rare occasion we use RJ11 phone cord we don’t stop to think if the cord is “reverse” or “straight” because it wouldn’t matter anyhow. Modern phones are not affected by the polarity in the connection.
This got we wondering: has anyone else had trouble with their Magic Jack when using it as line voltage inducer?
tl;dr: Magic Jack polarity issues- does it matter?
