Microcell - calls cut in and out on my end with voicemail and 3-way/on-hold calls

Call quality issues are most often related to line quality. Speed is only relevant if you can maintain at least a 3.0Mbps down and 512kbps up, which is one really needs for voice calls. I would run a VoIP test a couple of times at different times of the day and they post your results. Your internet can be fine but terrible for VoIP.

Android-based phones do have documented issues (Samsung acknowledges that) with the MicroCell but we needn't go into that now.

Are you using a separate router/modem with Charter or do you have a gateway? Have you ensured that ALL of the router requirements are being met as stated in the setup guide and my Tech Guide?

The MicroCell can handle multiple phones being used simultaneously with no issue, but we are seeing some issue with conference calls to one phone and I'm not sure what is going on. One possible theory is how your ISP is handling multiple VoIP calls to a single phone.

Maybe I'm missing something here.  I run the VOIP test listed in you tech guide and I get nothing.....

This is all I get.  No results, no output that I can find at all.

I am using a separate modem and router.  I've got the Charter issued Cisco SPC3216 modem and I'm running an Asus RT-N66U dual band modem.

I've read through all of your "Minimum Router Requirements" and I'll be honest.....like reading a foreign language.  I've tried googling some help but really I'm not sure if I'm doing the right thing, if your terms are interchangeable with what I'm finding for my specific router (forwarding vs. open), or if I'm just too ignorant on this.  With the different router manufacturers using different verbiage, procedures, etc........no, I can't guarantee that I'm meeting all ofyour minimum requirements.  I think I am, but I'm not a network engineer so I can't tell for sure.  I've forwarded the ports you list as follows:

Is this the same as opening them?  I dunno.

Ipsec passthrough is enabled.  Got that one!!

As far as the rest, I'm lost.  Don't get me wrong, I'm grateful for your help.  But really I don't understand a lot of your requirements or how to make sure they're set.

Thanks!

To run the VoIP test you need to have the current version of Java installed. Below the window you posted there should be another window, usually gray in color, that asks you to Activate Java.

Your ISP, Charter in this case, has to have the necessary ports open on their end. When you port forward you are assigning those open ports to specifically be available to the MicroCell. Giving the MicroCell a static ip address based on its MAC address adds an extra level of stability when you power cycle or lose power.

Unfortunately you'll need to check with Asus on how to check and configure your router. AT&T and us can't really help you because there are just way too many models of modems, routers, and gateways, with different firmware versions, for us to keep up with configs. Besides, we don't want to be messing with your network in case something goes wrong.

You also need to make sure that either the modem (Cisco) or the router (Asus) is performing NAT, but not both and that the modem is in bridge mode. Again, Charter is going to have to help you with all that. Sorry.

I just reported similar symptoms to AT&T.

1. Audio drops for first second on calls

2. On 3-way calls over the M-Cell, audio comes in and out every other second

I set up the M-Cell on my DMZ, meaning there is no firewalling of the M-Cell through my router.  I did that just to eliminate any potential firewall issues. My internet speed (from speedtest) is about 57Mb/s down and 60Mb/s up, so that should not be the issue.

AT&T is going to re-register my device to troubleshoot, then hopefully replace the device.  Any other ideas out there?

Conference calling and call-waiting work just fine for us on any of our iPhones. That being said, what we've seen quite often is the way the ISP and/or the router handles multiple calls to a single number. It's possibly due to prioritization which messes up the call quality. My guess is that single calls received/sent work just fine.

Speed is basically irrelevant as long as you can maintain at least 3.0Mbps down and 512kbps up, which is more than sufficient for voice. What is key is the line quality (jitter, etc).

I would suggest port forwarding to a statically assigned ip address of the MicroCell and not placing the MicroCell in the DMZ. That's what I do and I don't have any issues. It's at least something to try. Ensure that all of the other minimum router requirments are also being met.

It's possible that the MicroCell (you didn't say which model and how long you've had it) is defective, but at this point in time, I'd say not, and a new one will only have the same issue. If AT&T does send you a replacement MicroCell, make sure they include a new ac adatper as well. We've seen some odd things happen if the adapter is failing.

To check your line quality, go to voiptest.8x8.com, run it a different times of the day to get an overall average of the line quality and report back your findings. If memory serves me correctly it's Java-based so you'll need to have the current version of Java installed. The site will tell you or not.

Thanks OttoPylot - in response:

1. "My guess is that single calls received/sent work just fine" - they don't per my first item.  We dont hear the caller for the first second or so of a normal call (not a 3-way)

2. "the way the ISP and/or the router handles multiple calls to a single number. It's possibly due to prioritization which messes up the call quality." - sounds interesting, but how do we prove that is issue?  Also, the ISP does not know what is happening at an application layer, they just move packets.  So I think this is a Carrier (e.g. AT&T) issue.  My ISP is not AT&T.

3. "I would suggest port forwarding to a statically assigned ip address of the MicroCell and not placing the MicroCell in the DMZ." - that is how the MCell was previously configured, and I had the same symptoms.  I moved it to the DMZ specifically to remove the firewall as a potential cause of the problem.

4. The microcell is about a month old, it is the newer black Cisco model.  

5. Not sure why I need to test line quality with 60Mb pipe up and down.  Unless your test can actually detect packet loss?  Also, jitter is variable delay.  My symptom is a repeated, predictable drop - almost like audio is 1 second on, 1 second off.  To me that is not jitter.

Problem Update: AT&T support re-registered the device, the problem persists but only for the first minute or so of the merged (3-way) call.   In other words, the audio drops in and out, but then magically gets better during the call.  Totally confusing and also frustrating.  I will pursue a replacement.  Still interested in other theories and also more on what OttoPylot suggested about ISP issues.

If you have call quality issues with a single call then it is more than likely your line or how the ISP is handling VoIP. Unfortunatley that is something that AT&T has no control over. Line issues have to be corrected at the ISP level and most ISP's we've dealt with in the past with line quality issues will automatically blame AT&T. Your internet can be fine, and that's what you are paying them for, not to be a VoIP carrier for an AT&T product. As harsh as that sounds, it's the truth.

Again, your speeds are basically irrelevant. I have a nice introduction to VoIP in my Tech Guide (see link in my sig). Jitter can definitely affect voice quality. From the Tech Guide:

Jitter – this is defined as a variation in the delay of received packets. Data packets are sent as a continuous stream evenly spaced apart. Due to network congestion, improper queing, or configuration issues, the steady stream may be interrupted such that the delay between each packet can vary instead of remaining constant.

When the router receives the RTP (Real-Time Protocol) audio stream, it has to compensate for any jitter that is encountered. This basically means that the RTP has to be buffered and then put back together in a steady stream to be sent to the DSP (Digital Signal Processor) and re-converted back to an analog signal. This buffer is either called the playout delay buffer or the de-jitter buffer.

If the jitter is too large to be buffered adequately, packets are discarded which results in audio dropouts. Sometimes the dropouts are not noticeable if the DSP can insert packets that it thinks should be there (predictive insertion). If they are too large, audio quality deteriorates or the connection is dropped.

Jitter can only be fixed by your ISP.

It is possible that your line quality could be fine in which case something else is affecting your voice quality. The MicroCell is a dumb device in that it just sends data packets back and forth. There is no real configuration that can be done like there is for a router. This is why we recommend running the VoIP test a couple of times at different times of the day to get an overall average picture of your line quality instead of a single snapshot in time.

There are also some routers that just don't play nice with the MicroCell. That's why it is important for us to know that you have indeed verified the minimum router requirments as given in the Tech Guide and you have setup the the MicroCell in it's optimal configuration, which is a single ethernet connection to the router with no switches, PowerLine adapters, etc in-between. Anything that can affect the flow of data back and forth to the AT&T Mobility Servers will affect voice quality.

Who is your ISP and what kind of interent connection do you have?

dzpw0p:

I've been having very similar issues but with only one line (not 3 way). In and out for the first 20 seconds of ALL incoming calls. If I make the call, it does not do it. Have you had any new developements or fixes? 

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@c2praise wrote:

dzpw0p:

I've been having very similar issues but with only one line (not 3 way). In and out for the first 20 seconds of ALL incoming calls. If I make the call, it does not do it. Have you had any new developements or fixes? 

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Please see my post: https://forums.att.com/t5/3G-MicroCell/MICROCELL-ISSUES-UPDATE/m-p/5031109#M24843

Since I originally posted about this issue the MicroCell has been barely better than my original problem I was trying to fix - Samsung phone not recieving calls in my home office.  Then about a week ago things went down hill.  Every single incoming AND outgoing call, whether single or 3way call, cut in and out for about 10 seconds.  They can hear me, I can't hear them.  I finally unplugged and ditched the Microcell.  

BUT, it's not all bad news.  Sometime last year I noticed that on one of the Android system updates that the Wifi calling had been activated.  I started that about a week ago here in my home office and have had better results.  Incoming and outgoing calls seem to be working.  The only issue I'm having with wifi calling is that I can hear a pretty loud click during calls.  The people I'm talking to can't hear it, and yes, it's very annoying.  But I can send and recieve calls!!  I can't believe I'm actually excited about subpar phone service.  Yay.....feeling defeated again.