A Shared SC/LC, is a number used by multiple businesses. It is a code that is shared with multiple customers. The shared SC/LC are defined by the keywords. If you want to purchase a shared SC/LC, operator will ask you for a unique KEYWORD.
Example: ITEXT is a keyword and SC is 57575. Any subscriber who sends an MO message with KEYWORD ITEXT to 57575, Operator will route that message to your server.
A Dedicated SC/LC, is a number that only you can use. It is irrespective of the Keywords. Any MO message content sent to the SC/LC will be routed to your server.