How do I use keywords with sms?

A GSM Modem requires a keyword to be used. The reason for this there can be only one instance of the modem running on a computer so query requests must be distinguished by a unique keyword.

SMPP can have either of the following:

1. A unique SMPP mobile number for each query
2. Use one SMPP mobile number for all queries but separate each query by a unique keyword

Ideally it is better (but more expensive for the cost of each number) to use a unique mobile number as you can then add each mobile number to your address book instead of having to remember each keyword.