[BlackberryFan2009]

I have the 9900 on T-Mobile and I noticed my 4G keeps switching to GSM when making calls. I like texting & browsing the web while talk 2 someone on speakerphone, but can't if the 4G logo disppears and goes into GSM. Anyone else have this issue?

[antheauxny]

Turn on the wifi.

[belfastdispatcher]

I have the 9900 on T-Mobile and I noticed my 4G keeps switching to GSM when making calls. I like texting & browsing the web while talk 2 someone on speakerphone, but can't if the 4G logo disppears and goes into GSM. Anyone else have this issue?

You can still text while on GSM signal, sms doesn't need data contrary to popular belief.

I only get this when I'm on 2G signal and after a few minutes it changes to gsm but if I'm on 3G it stays on 3G.

[emirozmen]

Yes everybody's does.
If you want to access internet when making a call you need to be connected to wifi.

[Phill_UK]

Why does 4G icon keep switching to GSM during calls?

[BlackberryFan2009]

But this never happened on my BB Bold 9700/9780. When 3G was there, i was able to toggle between talking on speakerphone, texting, and web browsing, so why does this happen with 4G? Shouldn't 4G/HSPA+ or 3.5G be superior to 3G technology? Shoudn't a newer more advanced model function better?

I never had my Bold 9700/9780 on wi-fi to talk and do web at the same time. Can someone please clarify?

[BlazorBoy]

I think it is a combo if the phone (was not an issue with my 9700)and tmo's poor signal.