Go Back   Wireless and Wifi Forums > Cellular Communications > Australian Networks > aus.comms.mobile
Register FAQ Forum Rules Members List Calendar Search Today's Posts Advertise Mark Forums Read

 
Reply
 
LinkBack Thread Tools Display Modes
  #1 (permalink)  
Old 09-05-2007, 12:23 AM
BEMW
Guest
 
Posts: n/a
Default GSM modems - sim card question

Hope this group can help. I have 2 Wavecom Fastrack GSM modems that I
want to use to send data between a PC and an electronic sign. I have
tried to use sim cards from my normal mobile phone, but these only
appear to be registered for voice calls, not data calls. What type of
sim card or plan do I need to make these modems work. The volume of data
transmitted will be very low, maybe about 2k twice a week, just to
update the messages on the signs.

Reply With Quote
  #2 (permalink)  
Old 09-05-2007, 02:59 AM
John Henderson
Guest
 
Posts: n/a
Default Re: GSM modems - sim card question

BEMW wrote:

> Hope this group can help. I have 2 Wavecom Fastrack GSM modems
> that I want to use to send data between a PC and an electronic
> sign. I have tried to use sim cards from my normal mobile
> phone, but these only appear to be registered for voice calls,
> not data calls. What type of sim card or plan do I need to
> make these modems work. The volume of data transmitted will be
> very low, maybe about 2k twice a week, just to update the
> messages on the signs.


As a general rule, you will need to call the SIM's data number
to establish a data call. This will be a different number from
its voice number, and likely cost you an extra monthly fee.
Speak to your carrier.

The reason for this concerns the different over-the-air (OTA)
characteristics required for data, as distinct from voice.
Imagine a normal landline modem trying to establish a data call
to a GSM modem. How does the mobile network know whether to
establish the OTA leg with voice or with data characteristics?
The problem is solved by issuing different numbers for the
different call types.

Strictly speaking, a data call between two GSM modems /could/ be
established with a single number for the SIM, because you're
specifying a data call by the "ATD" command syntax on the
outgoing OTA leg. And that information is potentially
available when the network sets up the incoming call leg to the
recipient. In fact, you could once make a data call between
any two Telstra GSM modems by calling the voice number.

They stopped allowing that, but last time I checked you could
still get it to work if you asked for a V.110 ISDN connection
to a voice number. It's worth trying. Your modem command to
set the call type to V.110 is

AT+CBST=71

John

Reply With Quote
  #3 (permalink)  
Old 09-05-2007, 04:13 AM
John Henderson
Guest
 
Posts: n/a
Default Re: GSM modems - sim card question

I wrote:

> As a general rule, you will need to call the SIM's data number
> to establish a data call. This will be a different number
> from its voice number, and likely cost you an extra monthly
> fee. Speak to your carrier.


Whether you can /make/ data calls from a non-data SIM is a
separate matter from the ability to receive data calls. You
might be able to make data calls from the voice SIMs of all our
Australian carriers, although Optus might be an exception. But
I'm not sure. It's a long while since I had any up-to-date
info.

An easy way to test is to try making a data call from the GSM
modem and SIM to a normal POTS (fixed landline) phone. If it
rings, it's a fair indication that you can. There's no way of
signaling the call type within the POTS system itself.

John

Reply With Quote
  #4 (permalink)  
Old 09-05-2007, 09:51 PM
John Henderson
Guest
 
Posts: n/a
Default Re: GSM modems - sim card question

I wrote:

> ... last time I checked you could still get it to work if you
> asked for a V.110 ISDN connection to a voice number. It's
> worth trying. Your modem command to set the call type to
> V.110 is
>
> AT+CBST=71


I'd forgotten about possible use of the "single numbering
scheme" command facility. It's not something I've done myself,
and would depend on whether your carrier supports your making
data calls towards a GSM "voice" number.

It seems that you may be able to set up the default OTA call
type characteristics on the answering modem using the "AT+CSNS"
command.

AT+CSNS=4

sets the default incoming bearer up to "data" in situations
where the incoming bearer is not specified with the call
(otherwise the default will be "voice"). This is consistent
with my getting data calls through to voice numbers using
"AT+CBST=71" on the calling modem, since the bearer information
is undoubtedly passed through in that case.

Wavecom modems seem to offer the

AT+CICB=0

command as an alternative to provide this functionality -
setting up the default bearer type to "data" on the answering
modem.

So it's worth experimenting with "AT+CSNS=4" and "AT+CICB=0" on
the answering modem, as an alternative to trying "AT+CBST=71"
on the dialling modem.

Given your direct connection to a "dumb" display, you'd need to
make sure you can save any required answering modem settings as
defaults. This is especially relevant to Wavecom modems with
the recommended use of the "Wavecom reset", "AT+WRST" facility.

Please let us know how you go with all this.

John

Reply With Quote
Reply


« What have been or currently are,your favorite phone ringtones you've used ? | Nokia 6300 »
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
SIM Card Question Rolling Rock 33 alt.cellular.cingular 1 08-25-2007 05:03 PM
SIM Card question Jane alt.cellular.cingular 10 04-08-2007 01:14 AM
K800i memory card question Peter uk.telecom.mobile 2 03-10-2007 04:29 PM
Novatel Wireless U730 Card question Drew alt.cellular.cingular 1 01-03-2007 03:54 AM
Best fitting video card: NVIDIA (which brand?) or ATI (Sapphire)? Andrea Sansottera alt.comp.hardware 1 08-30-2006 10:12 AM


All times are GMT. The time now is 08:29 AM.



Powered by vBulletin® Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO 3.6.0 PL2

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45