Hi,
Every T3212 the MS is doing a location update, during the time of this procedure, the MS is in dedicated mode (on SDCCH).
I guess you could page the IMSI and send them a SMS. That would push the MS in dedicated mode, during the reception of the SMS.
There are some SMS that are “system” SMS, they don’t make the phone ring, they are not displayed by the phone… Well, I think it exists, I’m not sure.
regards
pix