Clickatell

Connnect to http://example.com/admin/build/modules
Enable Clickatel module in SMS Framework section.

Please note that Clickatel module only supports sending SMS, not receiving them.

Receiving SMS requires a phone number located in a country, which is billed every month.
Therefore, receiving SMS via clickatel was not yet implemented.

Clickatel account

Visit and sign-up for an account using the API option.

You will be asked to buy a minimum number of credits.
By the time of writing this tutorial, the number is 400.

Then go to the admin panel:
https://www.clickatell.com/central/manage_products.php

Add an HTTP connection:

Enter the following information:

• Name: for example "MySite".
• IP Lock Down: you may enter the IP of your website to restrict connection.
• Dial Prefix: example, 33 for France.
• Callback Type: ???
• Callback Url: ???
• Callback Username: ???
• Callback Password: ???

Validate.
You API ID is now visible.

Drupal admin panel

Go to http://example.com/admin/smsframework/gateways
Click on Configure on the Clickatel line.

You will be asked to enter:

• API ID
• Password
• Username

Click on Save.

If no error is returned, this works fine.