An interesting but probably not well known functionality of the SMS system are delivery reports. By default, requesting delivery reports is usually deactivated in the mobile device, so few people know about it. On Symbian phones, delivery reports can be activated in the SMS settings. Once active, the SMS Service Center sends a report back to the originator as soon as an SMS has been delivered, which is then displayed for a couple of seconds on the screen and also put into the "Delivery Reports" folder in the SMS application. So while this feature works well for SMS messages to other subscribers of the home network, I was wondering if it also worked when sending messages to other networks, both national and international?
The quick answer is yes. I tested this by sending an SMS to a SIM card of another national network operator and to SIM cards from network operators in Italy, Spain, and for the ultimate test, Thailand. To ensure the delivery report is not only sent in some cases once the SMS is received at the service center I only switched on the phone with the respective SIM a couple of minutes after the SMS was sent. In all cases the delivery report came in right after the SMS was delivered, i.e. right after the phone was switched-on and the SMS was delivered.
So in other words, SMS delivery notifications work even for international SMS transfers.
I was told it depends on what connection is used between the originating and terminating operator.
If it is via SMPP, I think the terminating operator always return with successful delivery even though it is not delivered yet.
Hi Nick,
interesting to know. In my case, then, all networks I tried were connected properly 🙂
Cheers,
Martin
Definitely depends on the operator. Here in the UAE I always get successful delivery responses immediately when sending SMSs internationally.
Delivery reports works fine in following two cases :
1) if both sender and receiver are on GSM network or
2) if sender and receiver are subscribed to same CDMA operator.
Issues with GSM-sender and CDMA-receiver and vice-versa. Also, issues with CDMA-sender and CDMA-receiver on different operators.
-Sunny
Receiving the SMS/text delivery confirmation is built-in the protocol (GSM) being used. But this can be overwritten by the carriers/service providers depending upon their business policies. Since the delivery confirmation is an extra message on the carrier’s bandwidth (I know it sounds cruel). For eg. here in US, AT&T does’nt do delivery confirmation (iphone).