The HTC One X+ is my favorite smartphone (for the time being). It's an incremental improvement over the One X (which as previously noted I am a fan of), and it is fast, and lightweight, the screen is perfect, the battery life is good, HTC Sense is useful and lightweight ... all in all it really is a superb phone.
It's also been a source of frustration as of late, in that every once in a while it will stop receiving phone calls. And although in truth I am using my phone less and less as, well, a phone, not being able to receive calls is a problem.
And in case anyone else is running into the issue, here's the scoop:
The problem I (and others) have run into (and since reported to AT&T) is that after a few days of normal operation the phone will just stop receiving calls. Outbound calls work, texts work inbound and outbound, all data works, everything works except for the ability to receive calls. Without warning or apparent trigger, callers will either hear endless ringing but no voicemail, or a few rings followed by a busy signal, or a couple of rings followed by a network error message. Nice, huh?
This first happened within days of receiving the phone, and AT&T replaced the SIM and things seemed to work, for a few more days. They next played with network settings which appeared to fix things at the time but in reality didn't. I then took the phone out of the country for 8 days and it worked flawlessly, until I returned to the US that is. The very next day it happened again. This time AT&T replaced the phone and the SIM, and this time the phone worked for two days, and then more of the same.
Over the past 5 weeks I have tried 3 different HTC One X+ devices and 4 SIM cards, and lots of other devices thrown into the mix for testing, and can I state unequivocally that this has nothing to do with specific phones or SIM cards.
The problem appears to be the phone falling off the right LTE bands. I can't figure out what triggers this, nor have I determined if it is the phone or the network (there seems to be a large number of complaints in the Metro Detroit area, so it may indeed be a local network issue), but what is happening is that the phone is switching from US LTE bands to international LTE bands (which explains why it worked perfectly outside of the country).
The fix is irritating but simple:
- On the keypad enter *#*#INFO#*#*
- Select "Phone information"
- Click on the menu and select "Select radio band"
- Click on "USA Band"
That will fix it. Until the next time you fall off the network, that is.
Unfortunately there is no way to know that your phone has gotten into this state until someone lets you know that you are missing calls. But, when it does happen, this will fix it.