**>From: "Baden de Bari" <[EMAIL PROTECTED]>
**>To: "Rafael 'Dido' Sevilla" <[EMAIL PROTECTED]>
**>Date: Fri, 17 Dec 2004 11:51:47 -0600
**>Subject: Kannel and GSM modems
**>
**>There are sites that post the SMS/GSM codes for most world-wide network
**>carriers. So Kannel uses a GSM modem to link up to these carriers?
**>
**>For example, if we want to send in the US and Canada, we would need some
**>sort of agreement with the network carriers to send to customers on their
**>networks? ie. To send a msg to a user in Canada using Rogers Wireless:
**>we have the number, and want to push the message to them.
**>
**>As I'm not too familiar with the use of GSM modems, I would like some
**>more in formation about how to use them with Kannel and how to link up
**>to world-wide carriers?
**>
Please send text-only mail to the mailing list. Some of us
don't use HTML-enabled mail readers due to many reasons.
I will reply to all three of your emails in this email.
GSM and CDMA are two different technologies to accomplish the
same thing: send voice and data to mobile terminal. These mobile
terminals can be mobile phones that support voice, SMS, data,
a pretty color screen, etc., or they can be modems that support
limited functionality (maybe just SMS and data).
GSM uses a Subscriber Information Module (SIM) to store
information on how to connect to the Mobile Network Operator (MNO)
that is his/her home operator. The SIM can be moved from one
GSM device to another. This allow you to use different
devices with the same SIM (allowing easy upgrades of phones)
or use different SIMs with the same device (allowing you to
try different MNO to see if they have better coverage or lower
pricing tariffs).
CDMA uses the International Mobile Equipment Identity
(IMEI) number (or equivalent) to determine if the device
(phone, modem, etc) is allowed on a particular network.
As a result, moving a device from one MNO to another requires
you to register your device with them.
The way Kannel uses a GSM modem is via the AT commands as defined
by the ETSI TS 07.07 specifications. Kannel sends AT commands
to the GSM modem (AT+CMGS to send an SMS, AT+CMGR to read
an SMS, etc.) and reads the responses. Normal procedure is:
1. Buy a GSM modem that supports the ETSI 07.07 AT commands
(some phones have builtin modems that support the AT commands)
2. Attach the GSM modem to the serial port of the host running Kannel
3. Get a SIM from an MNO
4. Get a phone number associated with the SIM (usually pre-assigned
by the MNO or you might be able to pick the phone number for
a list available from the MNO).
5. Plug in the SIM to the GSM modem.
6. Start sending and receiving SMS.
This procedure [minus steps 3 and 5] also works with a CDMA modem
so long as the CDMA modem also supports the AT commands in the ETSI
documents (my update to the userguide will list the requied AT command
set used by Kannel).
When you send an SMS, the message will originate from the phone
number assigned to the SIM. When someone wants to send you an
Mobile Originated (MO) SMS, they would send it to the phone number
assigned to your SIM.
Most MNO's will have roaming agreements with other MNO's so their
home subscribers can roam to the other MNO's network and still
have phone service (at higher cost). Ususally, the roaming
agreements also states that the subscribers from one MNO can
send SMS to subscribers on the other network. This allow for
someone in Hong Kong to send SMS to someone in France.
Since the MNO's have the agreements to pass SMS to other
MNO's, in the GSM world, you do not need to get an agreement
specifically to do this.
For CDMA, it's a different world. Text messages in the CDMA world,
was originally Mobile Terminated (MT) messages (i.e. the carrier
can send the message to you but you could not send a message
back [no MO SMS].). More recently, CDMA added support for MO SMS.
As a result, many CDMA MNOs did not have agreements to pass
SMS between each other. This meant you needed to get agreements
with each operator before you can send messages to their subscribers.
Nowadays, there are SMS aggregators that can provide you with
the means to send SMS to just about any subscriber. They have
made the agreements with the MNOs and will provide you with
a means to send (and sometimes receive) SMS. Some provide
connections that use HTTP, SMPP, etc., that Kannel will
use to communicate with them. In those, cases, you would
not need a GSM modem. But, you would need to get an account
from the aggregator and pay for sending/receiving the SMS.
See ya...
d.c.
