Simultaneous DATA and VOICE


Can the HL6528 do simultaneous voice and data (gprs class a) communication? If not, are there any other Sierra Wireless modules that can do that?



I haven’t used the HL6528, but a quick read of the specs indicates that it is a 2G (GSM/GPRS) device.

It’s my understanding of the 2G network that it can’t do simultaneous GSM Voice and GPRS Data. If a voice call is started, the GPRS data is ‘parked’ until the voice call is completed, whereupon the GPRS connection is unparked and the data transmission continues.

You may have better luck with the 3G HSPA HL8548 module - I don’t know enough about the way the HSPA network works to understand the way that voice and data are handled.

ciao, Dave


See Wikipedia GPRS.
GPRS Class A:

So I think the answer from Dave is not correct.



Thanks for the link.

I’ve been through the SiWi Product Technical Spec for the HL6528 and there’s no indication of which class (A/B/C) the module is.

I’ve done a lot of work with the Q2686, and it definitely behaves as a CLASS B device - capable of VOICE and GPRS, just not simultaneously.

Without the docs being explicit, the only way is to ask your distributor - or try it and see what happens!

ciao, Dave

Take a look at the AT+CGCLASS command. As you can see in the AT command guide Class A is not supported for HL6528.

Thank you.

So it would seem as if the HL8548 supports Class A then. Was actually looking at the HL6528 because of the dual sim, dual standby functionality, which the HL8548 unfortunately doesn’t support. Oh well, suppose one can’t get everything in life :frowning:

Hiya All.

Not having a HL6528 on my desk, I asked my distributor. They have confirmed that the HL6528 is a Class B module:

[12:33:35]+CGCLASS: "B" 
[12:40:46]+CGCLASS: ("B","CG","CC") 

However, this is only available from the AT commands guide (or running the command on a module) - not the Product Technical Spec (PTS).

It would be nice if system specs like this are in the PTS.

Such devices may well be available - but the HL6528 is not one of them.

The question is moot in Australia anyway - the major telco here (Telstra) has announced that the 2G network (GSM & GPRS) is being turned off in 2016. The other telcos (Optus & Vodaphone Aus) haven’t made any announcements yet - but I suspect that they too will turn off the 2G network in the not too distant future. So designing around 2G modules is over down here.

ciao, Dave

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You have all informations on “AirPrime HL6 and HL8 Series AT Commands Interface Guide”:

HL6528x: Only Class B
HL85xxx: Class A BUT:

  • only in UMTS Band
  • only for networks compliant with class A