This allows customers to send out SMS messages and also receive responses back. When using this feature, you are automatically assigned a random mobile number, which is then permanently assigned to your account. Every 160 character message you send out using the SRS uses 1.5 credits, rather than the standard 1 credit. All responses are received back into your SMS portal, so they can be viewed and responded to again, if required.
Advantages
Quick and instantly available to use
Allows conversations to be setup with customers quickly and easily
No cost to receive messages.
Disadvantages
If sending large amounts of messages, if can become expensive
No way of differentiating inbound customer texts.