I have been expereimenting with a new GSM burglar alarm and there is some strange phenomon with the SMS contol feature. Does anybody have any idea, why that older 2G phones and all telecom phones have no problems sending an SMS to my GSM alarm system. However, newer phones (not just 3G) seem to only work occasionally. Does anybody know why this could be?
The system has no problems sending out SMS to any mobile phone 2G 3G Telcom etc.