magicJack polarity switched?

[podor]

So, I went to dial out on my WE 2565 last night and I couldn't. Somehow, the polarity of my magicJack switched. The only thing I did different was hook up a new all in one printer. I had the line feeding through the printer then to my KSU. My first though was that the printer somehow switched the polarity internally. I pulled the line out of the printer and hooked it up directly to another phone and the same thing. Nothing else has changed, everything is correct. I made a little polarity cross adapter to make it work. I certainly don't want to re wire just because the magicJack is messing up. Has anyone seen this before? Is there something I'm missing?

[unbeldi]

What type and issue number of line card are you using in your KTS?

[podor]

WE 400h. It's reversed straight from the magicJack. I ran another phone at the unit itself.

[unbeldi]

WE 400h. It's reversed straight from the magicJack. I ran another phone at the unit itself.

Ok, the 400H should be universally useful no matter whether the line is floating or grounded.  Cards earlier, and 400D cards before Issue 15 or so required the line to be properly grounded.

I have not used a MagicJack so I haven't taken one apart to see how the signals are generated or whether one side of the FXS interface is grounded.

Just poking at tangible issues...

Which kind of MagicJack device is it? I think they have two or three types now.

[podor]

It's the "go". Everything is working perfectly otherwise. In fact, the receiver volume is better since (not sure if it was the printer or mj). It really works good, other than this little hick up. It has enough ringing amperage to ring a 500m that goes through an exclusion switch on my 565. So it goes through the KSU to the 565, then I have the 500 broken out from BL-V and O-V pairs after the exclusion. I really doubted it, but impressed so far.

[unbeldi]

It's the "go". Everything is working perfectly otherwise. In fact, the receiver volume is better since (not sure if it was the printer or mj). It really works good, other than this little hick up. It has enough ringing amperage to ring a 500m that goes through an exclusion switch on my 565. So it goes through the KSU to the 565, then I have the 500 broken out from BL-V and O-V pairs after the exclusion. I really doubted it, but impressed so far.

The ringing goes through the KSU ?
You don't have a ringing supply in the system?

[podor]

I have a 118a ring generator. The 500 rings through T and R from the KSU. It's kind neat hearing both ring patterns.

Just found this

http://mjcheck.low.li/2013/09/power-indicator-lights-and-standards-compliance-for-the-magicjack-plus-2014/

Doesn't explain the sudden change.

[poplar1]

The only reason I can think of for having reversed polarity from the Magic Jack is that this allows you to use a standard modular cord to connect the MJ to any of the house jacks. Then all the other jacks in the house will have the correct polarity. 

(Of course, the house wiring pigtail should be unplugged  from the phone company interface.)

[unbeldi]

I was under the impression that you have not changed the MagicJack unit from working before connecting through the printer to not working afterwards? Always the same unit, right?

So whatever the initial polarity was should not matter if it was wired correctly.

Many FXS devices, such as VoIP ATAs have the pins reversed, that is not unusual.  Even the Panasonic 308 PBX has its station ports reversed.  They do this so residential users can simply use a standard modular cord to plug the unit into their existing wall wiring to serve an entire residence.

Does the MagicJack update its firmware on the fly over the Internet automatically?
It's conceivable that in software the signaling polarity could be changed by reassigning the output pins of the microcontroller, but probably not highly likely, because generating 25V or 48V for loop current requires polarity sensitive components outside the microcontroller that can't just be switched.

[podor]

Just for clarification, the magicJack was wired directly to the printer, then out of the printer to the KSU. Polarity was correct until I switched to my new printer. After I hooked up the printer, I tried to dial out and nothing. For diagnostic purposes, I hooked up a non polarity protected princess phone directly to the magic jack with the same results. I made a little polarity cross box and everything works. Now, I'm not 100% sure if it was directly after the printer switch, but it is a little close to be a coincidence. I had Uverse before the magicJack with the same set up and no issue. Uverse always had the correct polarity, even with the princess phone. Thinking back, I had some issues with the printer when I first hooked it up to the magicJack. For some reason the DT wouldn't pass through. I'm not sure what I did to get it to work, but it did.

So, this is what I'm thinking. The magicJack was always backwards, but my old printer somehow corrected the polarity? I did a trade-in deal with Office Depot so I can't try the old one again. Everything works with my modification, so it's no big deal. I just have an uncontrollable need to know what happened.

[Phonesrfun]

Guys, I'm totally lost.

I understand connecting a Magic Jack to 1A2.  I also understand polarity issues with DTMF dials.  But, where the heck does a printer come into play?

[unbeldi]

I thought he has a printer with a phone-line protector.  Or not?  Now I am not so sure anymore either, frankly I can't remember having seen a printer with that.
Or are you using the printer as a USB hub?

[podor]

Sorry, it's an all-in-one and I use this line for faxing also. Sorry for the confusion.

Did a quick Google search and found a complaint about my exact old printer and polarity issues.

http://h30434.www3.hp.com/t5/Printer-All-in-One-Install-Setup/2-EXT-polarity-reversed/td-p/2767017

Maybe the printer is polarity sensitive and can correct it's self. Most people would never notice except us crazy phone collectors.

[unbeldi]

Well, the polarity between the two jacks on the printer should indeed be reversed.  The rest depends on the cords and the polarity at the MagicJack.

[poplar1]

So, this is what I'm thinking. The magicJack was always backwards, but my old printer somehow corrected the polarity? I did a trade-in deal with Office Depot so I can't try the old one again. Everything works with my modification, so it's no big deal. I just have an uncontrollable need to know what happened.

If your Princess doesn't work plugged directly into the Magic Jack, but it did when plugged into the EXT jack on the old printer, then that is because the two jacks on the printer were wired in parallel, i.e.,  the same. A standard cord reverses polarity, so when you added the second cord, it reversed it again. Two wrongs make a right?

You can do the same thing with a standard T-jack or splitter. Instead of plugging the splitter into a wall jack, use it instead as a junction to connect two 6-foot  cords together. Then plug one end of the now 12-foot cord into the wall jack, and the other into a polarity sensitive phone, and the polarity of the wall jack will be reversed inside the phone.