I got an email last week from Paul detailing how he was having problems with his T-Mobile 8320 and his Jawbone bluetooth headset. It turns out that when he made calls over UMA while on Bluetooth he would drop the call. This did not happen with his old Jawbone but only with the new Jawbone that was just released.
Paul then learned that UMA, WiFi, & Bluetooth all run on the 2.4 GHz band which may interfere with each other. T-Mobile even told him that there is no workaround for UMA and some Bluetooth headsets.
I know some people using the hacked (dd-wrt) Linksys firmware on their wireless networks have gotten a new feature called Bluetooth Coexistent mode which fixes this issue.
Has anybody else found a workaround? Are you also experiencing this issue? Feel free to help Paul out in the comments… 
Nikolaus Not Registered
Posted: June 10, 2008 at 9:40 AM EST
I also have the T-Mo 8320. As I understand it the WiFi UMA conflicts with other devices running on 2.4 GHz. The cordless phones T-Mo actually sells for use with Talk Forever Home Service run on 6.0 GHz because T-Mo has documented some interference for 5.8 GHz phone as well. I personally use two 5.8 GHz cordless phones with my Talk Forever Home Service, and have not had any problems on call quality at all. I would therefore propose not to use 2.5 GHz wireless devices, but stick to 5.8, 6.0, or other. T-Mo/RIM should be able to provide support on this issue. I have personally found them always helpful.
Paul Not Registered
Posted: June 10, 2008 at 11:11 AM EST
Hi – I’m the guy that emailed. Some additional color commentary: The new Jawbone is Bluetooth 2.0, and the old one (which works fine) is Bluetooth 1.5. So it may be a difference in the standard, or the power of the signal, etc. Either way, I just thought it might be of interest to people who were considering the new Wifi Pearl. It’s a shame because the new Jawbone was awesome, very small and light, great charging connection – they really solved some of the issues with the older one. I work from home and probably spend 3-4 hours per day on my UMA connection, so having a functional headset is kind of non-negotiable…
Mike Not Registered
Posted: June 10, 2008 at 5:14 PM EST
>Nikolaus
I believe that you are a tad off on the “6ghz”. The technology at use in the TMobile Hotspot at home Unlimited plan is actually “DECT 6.0” which is a revision of the DECT technology that Europe has used for many years. It actually operates at 1920-1930mhz, 1.9ghz.
The reason that 5.8ghz has interference, is simply because such a small wavelength has signal loss going through a sheet of paper, let alone metal, wood and brick. The lower the frequency, the easier it passes through objects.
More info can be found on Wikipedia; http://en.wikipedia.org/wiki/DECT
Nikolaus Not Registered
Posted: June 10, 2008 at 5:34 PM EST
Mike: I didn’t buy one of the T-Mo cordless phones, I just remember they rep in the store saying it was 6.0 GHz and was guaranteed to work with the new linksys router while 2.4 and 5.8 GHz they would not “guarantee.” If that was incorrect then that’s just what I was told by the rep.
mike Not Registered
Posted: June 10, 2008 at 8:30 PM EST from my BlackBerry 8320
I’ve been able to use my curve and my 8120 with my H680 and H12 on wifi
Carlos Not Registered
Posted: June 11, 2008 at 2:42 PM EST
I have the Tmo Curve and for my house phone i have Vonage.. and UMA will NOT WORK if Vonage is plugged in.. but once u unplug the Vonage Modem.. vulah!!! it works like a charm.. HOW Come?
Nikolaus Not Registered
Posted: June 11, 2008 at 5:09 PM EST
Carlos: MMmmm, that’s a pickle. I used ViaTalk (Linksys router) and my WiFi T-Mo UMA Router (also Linksys) together at the same time for about 6 months had never had a problem. Now I have the T-Mo Talk Forever Home Service ($10/month unlimited) and still don’t have a problem.
Do you have your routers fighting for the same IP? Could also depend on if you have your Vonage plugged into WiFi (maybe T-Mo) router, or WiFi Router plugged into Vonage. I used a non-T-Mo D-Link router for a few weeks, which worked by not perfectly. With a T-Mo Linksys wifi router worked much better. Best bet is to call T-Mo HotSpot support.
Mark Not Registered
Posted: June 21, 2008 at 1:19 AM EST
I am using the dd-wrt Linksys firmware with the Bluetooth Coexistent mode turned on but my bluetooth headset still does not function at all with the 8320 using uma.
Steve N Not Registered
Posted: July 3, 2008 at 12:35 AM EST
I have a similar problem. I too work from home and spend a great deal of time on the phone via UMA. I have a T-Mob 8320, WRT54G V5, Moto H700 and the new Moto H710. The H700 works fine with the whole setup and I am able to carry on business as usual. Unfortunately the H700 has taken some abuse and needed to be replaced. I purchased the H710 (which by the way is phenomenal on edge) and cannot place a call with it on UMA. It eventually forces the phone into edge, which is worthless to me as the package I am on is limited.
I ran across the post that you referenced concerning the DD-WRT firmware and the Bluetooth Coexistent capability. I was going to give it a shot but I just don’t know enough about flashing a router to feel comfortable doing it. Does anyone know a step by step guide that I could reference to flash the modem with my particular router version?
Or, does anyone know a really good router that would already have this Bluetooth Coexistent mode on it that I could just purchase? I am getting kind of sick of messing with this thing.
Luiz Fernando Not Registered
Posted: September 5, 2008 at 11:32 AM EST
Dear sir, please, remove the automatic translation feature (for Brazilian Portuguese, at least).
The results are truly awful, unreadable, and, sometimes, stating quite the opposite the writer wanted to say.
Another remarkable mistake is just above this window, in the “Leave a reply” note: the translated (!) Portuguese text is saying that “The replies are permitted only because the site owner is leaving his job”!!!
I hope he is not and hope faithfully that he’s going to take action against this horrible feature!
Thanks!
Will Smart Not Registered
Posted: September 8, 2008 at 2:30 PM EST
I started out my Tmobile UMA service with the Nokia 6301 and did not have this problem. I returned the phone and got a Blackberrry Pearl and do now have the problem. I’m stuck between two phones with incomplete features – the Nokia which does not support a bluetooth keyboard, and a blackberry that has this interference issue.
I will probably end up with the blackberry and turn off UMA after connecting using it if I want to use bluetooth.
Good luck.