When you are building your SMS dialogs, the messages that are sent to a mobile device are added to a queue of SMSs; in this situation, which is the default, the SMSs are sent to a non-specific slot.
When you send an SMS message to a mobile-device, this message is added to a queue of SMS messages managed by the end-user. This is the default behavior. In this case the SMS message is sent to a non-specific phone slot. However, in some situations, you might want to send an SMS Message the contents of which must be updated often, as explained in the next example; this behavior is implemented by sending the SMS to the same phone slot.
An SMS Message that notifies the user of how many emails are in the mail box. The eSpace sends a message notification that there are 2 emails; meanwhile a new email arrives for that customer, and a new message is sent, updating the information.
For the end-user it is not very pleasant to have two unread messages, since the content of the first message is outdated. To replace a message previously sent to the same mobile-device, simply send both messages to the same phone slot.
Send an SMS to a specific slot
You have to set the Phone Slot with the Phone Slot property. How?
When the phone slot has a specific value, the mobile device checks whether there is a message sent from the same originator and with the same phone slot. If this condition is true, then the previous SMS is overwritten.
Limitations of phone slot usage
When using the phone slot feature you have to consider the following limitations:
There are seven possible phone slots, due to protocol specification.
Not all mobile devices support this feature.
This feature doesn't work with messages bigger than 160 characters.
Send Message Properties