Setting up SMS integration to work using an SMTP gateway

2 minute read time.
I've not written much about SMS integration.  I did write one article some time ago here:
This is a feature that has been in the product and has been stable for a very long time.   There have been a couple of questions from partners recently indicating customers are starting to increase SMS messaging as part of their own customer communication strategy.  Instead of just relying on emails, SMS can be a very useful tool to provide prompts to customers in a timely fashion.     
The route we expect people to go down is using an SMTP gateway.   This allows a user to send SMS messages from Sage CRM via an email server. 
Here is how it typically works:
First, you need to find an SMTP gateway provider that supports SMS messaging. I think there are several providers used by partners and customers e.g. Twilio, Nexmo, or Clickatell.
Once you have signed up for an SMTP gateway service, you will typically be given an email address that you can use to send SMS messages. This email address will be specific to your account, and it will likely look something like this: [email protected].
To send an SMS message using the SMTP gateway, you can simply compose an email in your email client or email server, and then send it to the email address provided by the gateway. In the "To" field, you should enter the phone number of the person you want to send the message to, followed by the domain name of the gateway.
For example, if you want to send an SMS message to the phone number 555-123-4567 using the SMS gateway provided by Twilio, you would address your email to [email protected].
This is configured in Sage CRM within the Email Configuration Screens
Administration → Email and Documents → Email Configuration
In the body of the email, you can include the message that you want to send as the text of the email. Keep in mind that SMS messages are limited to 160 characters, so you will need to keep your message brief.
When you send the email, the SMTP gateway will receive it and then convert the email into an SMS message. The message will then be sent to the recipient's phone number.
The recipient will receive the SMS message on their phone, just like they would receive any other SMS message. The message will come from a phone number that is associated with the SMS gateway provider, rather than your own phone number.