What is happening with 3G?
Avedis53's profile

Professor

 • 

2.2K Messages

Monday, February 18th, 2013 4:49 PM

Mcell requires power cycle every day to regain connection to iPhones

While I didn't encounter this problem initially when I started up my Mcell a few months ago, it has now become a daily ritual that I hope someone here can help me with.

 

My setup:

 

Motorola SB 6120 modem -> Netgear WNR3500L router -> Mcell

 

The Mcell is connected to the router with a pair of Netgear Powerline 200 Nano Adapters because my modem and router are located in the basement with no exposure to window for the Mcell to see a GPS satellite.  The connection is good.

 

My Charter ISP connection is 30 mbps down and 4 mbps and is rock solid.

 

What's happening and what I've done so far:

 

Usually once a day I will no longer see the AT&T Mcell indication at the top of my iPhone 5.  When I check my wife's iPhone 4S she has also lost the AT&T Mcell indication.

 

Turning the phones off and then on does not bring back the Mcell connection.  Switching Airplane Mode off and then on does not bring back the Mcell connection.

 

The Mcell has all solid green lights when I go to check it after seeing the lost connection.  If I power cycle the Mcell, the phones will then show an Mcell connection again until the next time they lose the connection which is usually once/day but not at any particular time.

 

I have the latest firmware on all devices.

 

When I check my router's admin page after a lost connection, the router indicates that the Mcell's IP address has not changed and it remains the same after power cycling the Mcell.

 

On the WAN page for my router, I have set the MTU size to 1492 and set the NAT Filtering to "Open" instead of "Secured".  No improvement after doing so.

 

Suspicious of the Powerline Adapters, I tried disconnecting and reconnecting the Ethernet cable from the Mcell to the Powerline Adapter to mimic a temporary loss of connection to the router to see if that affected the Mcell connection.  The Mcell connection was not lost.

 

I have not set any open ports or a static IP address for the Mcell yet.  Is what I'm experiencing indicative of this solution?  Does anyone have any other thoughts as to what try next?

 

I don't want to waste my time with an AT&T Level 1 tech support person because their suggestions are almost always worthless.  I have better luck contacting user forums and that is why I'm posting here.

 

Thank God I was able to convince AT&T to give me a Mcell for free because if I paid $200 for it, I'd be very upset right now.

 

Thanks In Advance!

 

Avedis53

 

 

___________________________________________________________

MicroCell Technical Guide by Otto Pylot


I am not an AT&T employee.

Professor

 • 

2.2K Messages

11 years ago

Ok Otto,

 

I received my 3rd Mcell today. (Date code: 03/13; HW version 3.2).

 

Curiously enough, after deactivating/reactivating the previous Mcell, I did not find a lost connection this morning.  One day fluke or was my issue resolved by deactivating/reactivating the Mcell?  Maybe I should have tried that earlier but they didn't suggest it. 

 

The tech support guy is suppose to call me back and see how things are going after I got the replacement Mcell.  I'd like to be able to report what perhaps might be useful information to him and since I have 10 days to return the "defective" Mcell, I think I'll give the Mcell I am suppose to return a few more days of operation to see if the Airplane Mode toggling issue has gone away.  I want to see if deactivating/reactivating the Mcell really resolved the problem.

 

Regardless, I'll keep the Mcell I was just sent and send the other back after my experiment is concluded.

 

ACE - Expert

 • 

23.9K Messages

11 years ago

You have a more recent hardware version than mine so it should work. I would keep it as long as you possibly can (maybe 8 days) before sending it back just to make sure. Deactivating/reactivating has worked for some in the past and for some reason I thought you had done that way back when. If I didn't suggest that, that's my bad and I apologize for that. But, if the new works, you have the most recent hardware version Smiley Wink

Professor

 • 

2.2K Messages

11 years ago

Otto, we gotta stop meeting like this......

 

I received Mcell #3 on the 10th.  I left Mcell #2 operating to see if activating/deactivating it solved the problem.  After one day of no drops, Mcell #2 dropped connection to both iPhones the next night.  I ditched Mcell #2 and activated Mcell #3 on the 11th.  Mcell #3 was still dropping the connection overnight and I am able to reconnect by toggling the Aiplane Mode on the iPhones.  On the 14th, I disabled the Mcell handoff feature but this morning (the 15th) I had lost the connection again and toggled Airplane Mode to reconnect.

 

So what do I know now?  I would say that it isn't the Mcell that is causing the problem but I haven't heard from the tech support guy who was suppose to call me after I received Mcell #3 to see how it is doing.  Without the error codes, I'm flying blind here.  One would like to think that AT&T's Mcell system keeps a log of time-stamped error codes for each Mcell but who knows?  Perhaps it only saves the last code.  Without interaction with the tech support guy, I'm running out of things to try.  Of course, when he called me, my Caller ID showed "Unknown" so I have no way of contacting him directly.  Perhaps AT&T does that for a reason.

 

I keep coming back to the fact that I can leave my house with my iPhone and when I come back, it connects to the Mcell.  Yet our iPhones can be in the house, have automatic handoff disabled, have 4-5 bars of signal strength to the Mcell and still lose connection to the Mcell by the morning.

 

The only thing I can think of trying is to take the Powerline adapters out of the equation.  There could be a ground loop problem due to my house wiring or some other Powerline adapter issue that is causing the Mcell to momentarily lose its connection to the Internet.  Perhaps when an Mcell loses connection in this configuration, due to its design, automatic reconnects to cellphones don't occur. 

 

But then I ask myself, why just at night?  Also, I've disconnected the Ethernet cable from the Mcell in the past for several seconds to mimic a lost connection and that hasn't duplicated this problem.  I am also showing all solid green lights in the morning.

 

Still, I think it I need to verify if the Powerline adapters are the issue.  Hard wiring the Mcell directly to my router isn't an option because of the location of my router doesn't provide the Mcell a good GPS view unless I string 30 feet of wiring to get the Mcell to a window location.  One thing I can try is to hard-wire my Mcell to my WiFi repeater which is on the same floor of the house as my Mcell is.  I don't know if this will work but it would eliminate the use of the Powerline adapters.  I've got nothing to lose by trying it so I'll report back when I have more to offer.

 

Maybe toggling Airplane Mode isn't so bad after all......

ACE - Expert

 • 

23.9K Messages

11 years ago

Maybe I should put you on my Christmas Card list now Smiley Wink

 

I've always been uneasy about the PowerLine Adapters. In theory, they should work fine. But I know they can be spotty if your in-wall house wiring is not trouble-free. It could be that the MicroCell is more sensitive to line condtions in that scenario. Being as this is the third MicroCell that has exhibited the same symptoms, that indicates to me it has something to do with your setup and not necessarily the MicroCell.

 

Can you use a GPS extension antenna? They aren't that expensive (at least most of them) and you could run a thin cable up to about 70' to a window (at least the last time I checked, which was quite a while ago).

Professor

 • 

2.2K Messages

11 years ago

An external GPS antenna could work but the fact remains that the Mcell needs to be centrally located in my house for adequate coverage.  Putting it in the basement with my router would not cover the house even if I could get a GPS lock with an external antenna.

 

First things first though.  I have connected the Mcell to my repeater and it is functioning.  Powerline adapters are out of the system.  The Mcell is in a different location than it was but it still close enough to a sliding glass door to maintain a GPS lock (hopefully).  I have all solid green lights at the moment.  I've got 4 bars in the basement.

 

Fingers crossed....

ACE - Expert

 • 

23.9K Messages

11 years ago

Fingers crossed here as well........

Professor

 • 

2.2K Messages

11 years ago

While the problem with my first Mcell was somewhat different, I would agree that the issue with the last two Mcells does not now seem to show that they are at fault, especially after taking the Powerline adapters out of the system.

 

Since disconnecting the Powerline adapters and hard-wiring my current Mcell to my WiFi repeater, I have not had a lost connection over the past two days.  This is very encouraging needless to say.

 

This house is over 50 years old and the AC wiring codes were not the same then as they are now.  Specifically, the lack of adequate grounding on the AC outlets themselves.  While it appears that the junction boxes are grounded, the AC outlets that are mounted in the junction boxes are not grounded to the junction boxes.  In fact, the original AC outlets do not have a third prong (ground) to receive today's plugs.  As I have gone through the house and painted rooms, I have replaced the AC outlets with the three prong type.  However, grounding those properly has been a problem as access to a grounding wire has not been available in every case.

 

I had a satellite TV system installed in this house several years ago with multiple receivers and the installation guy couldn't get them to work initially.  It turned out that having multiple receivers that didn't have a true common ground was the cause of the problem.  Digital equipment like that is very finicky about ground loops.  The problem was resolved by driving a grounding rod into the ground outside by the connection blocks for the satellite system and wiring the rod to the blocks, thus establishing a true common ground for all the satellite receivers in the house.

 

Remembering that incident now, it makes sense that digital communications (Powerline adapters) across my home's AC wiring could have similar problems.  I do not have any knowledge concerning communication protocols between a Mcell and a router.  One might think that it could be an issue with this particular router but since I have so many other items connected to my router without any problems, I have to conclude that the digital signal between the router and the Mcell is being corrupted somehow by a ground loop problem with the Powerline adapters. 

 

The design of the Mcell circuitry apparently does not automatically recover its connection with the iPhones once the Mcell connection to the router is lost in this particular case.  Simply unplugging the Ethernet cable to simulate a lost connection does not accurately mimic the problem since my iPhones maintain their connection when doing so.  I would have to conclude that some bits are getting corrupted in the communication protocol between the Mcell and the router by the Powerline adapter's ground loop problem.  The Mcell sees a lost connection to the internet and drops the iPhone's connection and in this case, the iPhones have to re-establish a connection to the Mcell through an Airplane Mode toggle in order to clear the communication corruption in the Mcell.  This is conjecture on my part but it sort of makes sense.

 

At any rate, I don't think Powerline adapters are inherently problematic when used with a Mcell if the wiring system of the house is done correctly.  Otto, since you are the keeper of the holy knowledge of the Mcell, I would suggest that you tuck this bit of information away in your troubleshooting database and add the question about Powerline adapter usage when responding to Mcell users with a problem like mine.

 

I'll post back after I get several more days of Mcell operation without Powerline adapters.  If there is no repeat of the problem, then it has been solved.

ACE - Expert

 • 

23.9K Messages

11 years ago

Thanks for taking the time to post a very clear and concise of explanation of what you have done. PowerLine Adapters do work very well for most situations but you are correct, the house wiring needs to be very clean and modern. Older wiring may still be adequate for extending an internet connection and any momentary drop in current or grounding issues won't drastically affect your connection because the router can quickly recover and maintain the connection, but the MicroCell seems to be especially sensitive to line conditions with a much tighter threshold. This info will definitely go into my FAQ that I'm putting together. I also have a conference call with other ACEs and Support next week and this is one of the items on my agenda. In fact, there are supposed to be a couple of "MicroCell Experts" on the call so we'll see. Keep me posted.

Professor

 • 

2.2K Messages

11 years ago

Since removing the Powerline adapters from my system and hard-wiring the Mcell to my WiFi repeater, I have had zero dropped connections for the last eight days.  I have no doubt now that there was some sort of packet corruption going on while using the Powerline adapters which was the source of my problem.  Needless to say, the adapters have gone back in their box for now.

 

If anyone wants to buy a pair of Netgear Powerline Nano 200 adapters, I'll make you a really good deal.

ACE - Expert

 • 

23.9K Messages

11 years ago

PowerLine Adapters are #3 on the list of items to discuss with support tonight on our conference call. It will be interesting to see what they have to say. Thanks for the timely update. I always felt that your issue was related to the PowerLine Adapters but unfortunately it took a lot of troubleshooting on your part to determine that. The MicroCell must be very sensitive to line fluctuations that otherwise doesn't noticeably affect the rest of the internet connnection.

Not finding what you're looking for?
New to AT&T Community?
New to the AT&T Community? Start by visiting the Community How-To.
New to the AT&T Community?
Visit the Community How-To.