How to send a "silent message"?

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Mark Smith
New member
Username: Marksmith

Post Number: 1
Registered: 01-2007
Posted on Tuesday, January 09, 2007 - 06:54 am:   


I want to send a "silent message" to a handset - i.e. a message that is received by the handset but is not displayed to the user, and no notification is displayed to the user that any message has been received. The message needs to be received as I want to be able to receive back a delivery notification if the handset is active.

Is there a way to do this with NowSMS?

My initial ideas after looking through the discussion board are:
1. Send an MMS message larger than 30k. As 30k is the limit the phone should just discard any MMS larger than this size ad not inform the user? This would be more costly than sending an SMS so I would rather avoid this.
2. Send an OTA message with the NETWPIN set, but set the wrong NETWPIN.
3. Specify a flag in the UDH - e.g. set the message as a message to turn off the voicemail indication. This would be a good solution but is not completely "silent" - e.g. if the user currently has the voicemail sign active they may notice it is now not active. PDUSpy has an option to create a "silent" message but creates a UDH of 01 02 00 00 which I think would turn off the voicemail notification?
4. Send a malformed message. This would not be able to be displayed by the handset, but a lot of handsets may display "unable to display message here" or similar?

Thanks for any suggestions on this topic.

Mark Smith
New member
Username: Marksmith

Post Number: 2
Registered: 01-2007
Posted on Tuesday, January 09, 2007 - 07:01 am:   

I forgot to say, I also thought:
5.Send a Replacement message Short Message Type 4, or similar. Because the handset has not received a message from the originating number previously would the handset just discard this message or display it as a new message?
Malcolm - Now Support
Username: Malcolm

Post Number: 86
Registered: 12-2006
Posted on Wednesday, January 10, 2007 - 07:45 pm:   

Hi Mark,

I think #3 is the the only of the ideas that would work. But it would have the side effect that you mention.

The other techniques are likely to generate some type of message on a significant number of real world handsets.

I ran this by one of my colleagues, and he indicated that he seemed to remember an SMS message type 0 message could be sent to accomplish this. This is similar to your #5, as message type 0 is encoded in the PID ... value = 40 (hex).

My colleague said that there was a past thread out here that discussed some issues with this message type and a similar requirement.

I'm not having any luck finding that thread. But trying some quick tests with PID=40 seems to be accomplishing the desired effect for me.

Now Wireless Support