Prepaid 4G Data Sims

From time to time we get inquiries from folks traveling to the US from overseas, or just in a mode where they need to use USB modems on a temporary basis and want to buy their data on a prepaid SIM.  I just went through all the hoops associated with this on both Verizon and AT&T so I thought it was a good time to share. This isn't the only way to get it done, but I found that if you go into a shop and ask for a prepaid USB modem account, you'll be met with a blank stare and a couple of hours of confusion.

First, you'll really want to invest in a modem for the particular network you're targeting, in order to avoid high costs and diversions to 2-year agreements. Ebay is your friend here. For Verizon, always choose the UML295, as it's the only USB modem to support their XLTE band. For AT&T, either the Aircard 313U or the "Beam" will work well. The Beam is a bit nicer because the display on the modem will give you your data balance. If you choose the Beam, be sure to update its firmware on a computer, as Comrex codecs now only support the latest.

Expect to pay around $50 on Ebay for each of these modems.

The approach from here depends on the provider:

Verizon

By far the easiest way to get prepaid data in Verizon is to carry a Verizon-capable iPad (or Android tablet) into the store. Borrow one if you must. For $50, they will load it with an LTE SIM with 6GB of data attached, enough for several days of audio codec and several hours of video codec use. If you use an iPad, you'll probably need a SIM adapter to fit the Apple-centric "nano" SIM into your UML295 (which uses a micro-SIM). Adapters are available at the shop or easy to get on Amazon.

With Verizon, the alternative is to get a "Jetpack" hotspot SIM (again, Jetpack hardware is cheap on Ebay) and move that to the modem. You'll probably need to cut that down to fit the micro-SIM format. For some strange reason, prepaid hotspot plans are more expensive ($60 for 3GB) than iPad plans.

Make sure your SIM is active and working on your "dummy" device before leaving the store. Also, make sure it uses LTE, and isn't locked to 3G for any reason.

Verizon will always get you for a $35 activation fee for a new account.

AT&T

AT&T iPad SIMs don't work in modems (learned that the hard way). You will need to buy a prepaid hotspot SIM here. But the cost is the same ($50/5GB). AT&T is more open about devices, so the store reps should have no trouble getting your account going directly on the USB modem (just make sure to bring your laptop). Like at Verizon, make sure your modem is running in "4G LTE" mode, and be aware AT&T offers "4G" without LTE which is slower (and which you don't want to be locked into).

Tips for both

1) Make sure they are putting you on a prepaid plan, and not a monthly one (which is different still from a post-paid contract plan). With a monthly, you are subject to overages, and you might not like the results.
2) Make sure your plan doesn't auto-renew (unless you want that). It seems that until recently, auto-renew was the default. But both the Verizon and AT&T plans I got were set to "non-auto renew" by default.
3) Using your SIM's phone number, you can create an account online and recharge your SIM whenever you want. Unused data disappears one month after you load it, so only buy what you need.
4) If you don't reload your card for three months, the carrier will deactivate it and you won't be able to reload it anymore. You'll need a new SIM. At AT&T, this is free, but Verizon charges $35 to activate a new pre-paid account.
5) Remember that if you prefer, you can always leave the SIM in your hotspot or tablet, and tether to your codec via Wi-fi. Note that not all tablets support this on all networks, so do your homework first.

Microsoft kills Skype support in STAC-VIP

We at Comrex spent the better part of a year developing what we felt was a very cool feature in our STAC-VIP product--the ability to integrate with Skype. At the time, the Skype folks were invested in this and helpful. We even had to run the certification gamut, sending a sample to Estonia and having to make all sorts of adjustments to meet their requirements. But it passed, and we were able to introduce the first pro-broadcast gear with Skype support. We were very proud, and it has been received very well.

Enter Microsoft one year ago, purchasing Skype  The first thing they did was to kill the program that allowed us to integrate, called Skypekit. But we were already past the goal line, and they assured us they would still honor registration requests from our products indefinitely.

Today we got notice that STAC-VIP (or any other Skypekit-based products) would be retired from the Skype network on August 4. This means your STAC-VIP will likely be unable to register with Skype.

As you can imagine, this is a big disappointment to us. It will certainly cause frustration with some VIP users. There's nothing worse to us than unhappy customers, and when making them happy is out of our control it just adds to the pain.

We've tried to get Microsoft to reconsider, but things look bleak. As an alternative, we recommend considering WebRTC for use with STAC-VIP. Please have a look at our new technote.

Edit 8/14/14: For clarity, Microsoft has informed us of their intention to disallow STAC-VIP to register on the Skype network, even if your unit is currently registered. The units in our lab are still registering and working as of today, so obviously Aug 4 was not a hard deadline, but they are very clear that this will not be the case soon.

Universal LTE devices exists

Since we've been supporting 4G modems in our ACCESS and LiveShot products, we've been on a search for a USB modem that works worldwide on any network. The problem is that, while LTE is a good standard, every region has different LTE bands active and no USB modems exist that cover everywhere. The worst offender is the US, where each carrier occupies a hodge-podge of different bands, not to mention the different 3G standards deployed. So there isn't even a common American modem out there (it would certainly make development easier if there were!)

But there is one device that contains an unlocked LTE modem compatible with virtually every 4G network worldwide--The Apple iPad Air. Apple made the decision to make only one version of the Air for use worldwide, and the compatible band list is mind-boggling, covering every 4G and 3G network we've ever encountered, including every American band and modulation. And it's only sold unlocked, to be used worldwide.

It's not as elegant as a USB modem, but the Air can easily be put into "tether" mode, allowing Comrex gear to connect to it via Wi-fi, and sharing the LTE connection.

I've done my share of Apple whining here, but this is one time they did us a solid.

Edit 9/10/14
Neglected to mention that the latest iPad mini also features this latest universal LTE modem, as well as the newly announced iPhone 6. Now we just need one in a USB form factor!

Linphone is the Best Free Codec App

As you may know, Comrex doesn't publish its own mobile phone codec app. We feel there are so many strong third party offerings we prefer to concentrate on making our hardware codecs compatible with as many of the best ones as possible. Luci Live and Luci Live Lite are examples of good, pro-grade apps that talk to our codecs. But some users feel that if an app isn't free, they don't want to try it.






There are good apps in the free realm, but they've generally got one or two drawbacks like:
* G.722 only
* Not iPhone compatible
* Require registration to a SIP provider
* Not really free (require in-app purchase for wideband)

Now that ACCESS and BRIC-Link codecs support Opus, we can recommend Linphone, available for iPhone and Android, as our preferred free app. It doesn't have any of the previous drawbacks, and works great. See our new guide on how to configure Linphone.

Connect to ACCESS and BRIC-Link from any computer

With absolutely no software installation required.

Update 7/30/14: A new, easier way to do all this has now been posted, along with technotes for ACCESS/BRIC-Link and STAC-VIP.

I've been teasing Opus and WebRTC for awhile, and I'll have a lot more to say about it after NAB. But until then, let me leave you with an experiment. This will allow you to run a remote broadcast from pretty much any computer (or Android phone) to your ACCESS or BRIC-Link codec using the Opus algorithm via WebRTC. It's also a great exercise in getting familiar with WebRTC. Here's the instructions:

1) You'll need to upgrade your codec to firmware 3.0. Beware this is an unreleased beta test version, so there could be unknown bugs. ACCESS Rack firmware is here and BRIC-Link firmware is here. Instructions on how to upgrade are on our support page.

2) Go to http://ekiga.net, and apply for a free SIP address. You'll be emailed a username and password. Note we would normally recommend our favorite free SIP provider, getonsip.com, but their addresses are incompatible with this service.

3) Enable your codec to accept NACIP/SIP calls.  This is the option that lets you accept calls from other codec brands. It's found in the System Settings Tab (advanced options) under N/ACIP SIP Settings->Accept Incoming Connections. Click "enabled". (Hint--uncheck this after use if you don't want your codec to answer random incoming SIP calls)

4) Also on the web UI, enter the SIP parameters for your ekiga.net account:
* Use SIP Proxy -> enabled
* SIP Proxy address-> ekiga.net
* SIP username -> <ekiga supplied username>
*SIP Password -> <ekiga supplied password>

Once applied, you can check registration status on the  Connections tab. SIP Status should read "online (200 OK)".

5) Go to http://click2dial.org and choose "sign up". Give a valid email address, and you'll receive an email with two pieces of information:
* Your login password
* A web link. Copy that and store it somewhere. This is what you will send to anyone you want to connect to your codec.
You'll need to validate your click2dial account via the link provided.

6) Go back to click2dial.org and log in with your email address and password. Go to "My Account", and under step 1, choose "add a SIP address". Enter the ekiga address in the following format: sip:<user_name>@ekiga.net

7) The only other thing to worry about is whether the SIP RTP ports to your codec are open. If you're on the public Internet with no router or firewall, you're good to go.  If not, and your router isn't kind to SIP traffic, you may need to forward UDP 6014 and 6015 to your codec.

8) To connect, you'll need a computer with a speaker and a microphone. WebRTC won't function without a mic on the dialing computer.  A USB headset works best, but WebRTC also has a built-in echo canceller if you're using a laptop speaker/mic. Open Chrome or Firefox and go to the link provided by click2dial. You'll be prompted for permission to use the mic. When you allow that, you should establish a nice, low delay, full-duplex Opus audio link to your codec! Even works on Firefox and Chrome for Android. Sorry, no support for iPhone (ask Apple to support WebRTC!)

Let's have a little fun with this. The first user who successfully completes an Opus call from a browser, and sends us a screenshot of the codec's web UI showing a successful Opus call, gets some nifty Comrex swag. Send your screenie to techies@comrex.com. I'll make an update here when we've gotten the winner.

Update 5/5/14: The challenge has been met! Also I updated the Comrex firmware links to the latest version, which fixes a few WebRTC-related bugs.

Update 7/30/14: A new, easier way to do all this has now been posted, along with technotes for ACCESS/BRIC-Link and STAC-VIP.

Here's some of the fires I've been putting out this week

In my role as chief first-responder to technical "fires", I thought it might be interesting to share a couple of the typical glitches we hit here day-to-day. These concern our VIP-QC app, which was designed to be the world's simplest high-quality mobile streaming app. VIP-QC allows "one-button" connect to participating stations that use the STAC-VIP talkshow system.

First, all of a sudden I got word that the app was working fine on phones that are connected via Wi-fi but failed when on the Verizon Wireless network. Weird, right? The answer was in getting packet captures of what was leaving the phone and what was arriving at the STAC-VIP. Here's one of the lines in the "SDP" header, which defines a lot about the outgoing call you wish to make. This is what we sent:
o=MxSIP 85321307875255471 85321307875255472 IN IP4 74.94.151.146
and here's what got through to the other end:
 o=MxSIP43039135937389542286 3039135937389542287 IN IP4 70.192.23.167

So the working theory is that Verizon is processing SIP calls through their wireless networks through an "ALG" that alters a lot of the information sent between devices. This might not be all bad if it works, but if you look closely you'll see the network badly "munged" the line, losing a space and reducing six fields to five. Any device trying to interpret that will fail.

Beyond that, there's also a reported issue that the app now fails when the STAC-VIP you wish to call is registered with our preferred provider, OnSIP. OnSIP is great because they handle the problem of NAT translation very elegantly, and offer free accounts at getonsip.com.

This is a little deep in the weeds, but the problem appears to be with what should have been a benign change with OnSIP accounts. One of the things about our app is that it's extremely simple--no SIP registration is required on the app side to make it work. It just blindly dials any SIP URI programmed as associated with a particular station. This works fine with OnSIP, as they accept calls to SIP addresses without the user needing to be registered on their network (this is fairly gracious behavior and not all providers support this, but it makes the VIP-QC app work).

Like a piece of mail, a SIP call has a destination and return address. Because VIP-QC doesn't register, it creates a dummy "from" address by copying parts of the "to" address. So if it's calling gary@vipuser.onsip.com, the "from" field is set to <mac address of phone>@vipuser.onsip.com.

The change OnSIP appears to have made detects when a call is made from an OnSIP user, and challenges for a password. If the "from" field says it's from a non-OnSIP account, the call proceeds normally. Since VIP-QC made up the dummy OnSIP account, it aborts the call when challenged.

How do we fix these issues? We're working on hacking the app a bit to work around both. Hopefully, we'll have an update soon. In the meantime, try to avoid Verizon Wireless and OnSIP as provider for VIP-QC.

The Porcupine Hat

It's the internal working name for this:

Our thinking on LiveShot has been pretty consistent--with the advent of 4G, a pair of modems should be more than enough to get to the "sweet spot" of 1-2Mb/s for live video. But we've been up against two things:

1) Areas of the world where 4G is not yet deployed

2) Folks who simply believe more is better and will not try LiveShot without more modem support

The hat (officially called the "LiveShot Hub") clips to the top of the present LiveShot and provides a distributed row of USB ports at varying heights.

It's been a concern of ours since LiveShot early development that multiple modems have enough "spacial diversity" to prevent degradation of one modem's receiver while the other is transmitting. As you can see, the design of the hat allows for up to six modems to co-exist in a small space, while providing a maximal difference in space and orientation to allow lots of options for each modem's polarization. We'll be demonstrating it at NAB next month and shipping it this summer.