Please guide me on how we can attach PDF doc to a FAX message . Also, would like to know the attachment limit
You can send fax with PDF, all you need is to create a multipart/mixed request and add each PDF as an attachment. You can either send the raw bytes or base 64 encode the file.
There are many way to do this with C# is to use (alpha) SDK which is available on Nuget and GitHub:
Get the package from Nuget and follow the fax instructions under "Send Fax" on the GitHub link.
Ref: https://forums.developers.ringcentral.com/questions/226/how-to-attach-pdf-to-a-fax-message.html
Using the RingCentral Phone for Desktop, you can dial or receive test calls, send and receive test SMS or Fax messages in your sandbox environment.
Download RingCentral Phone for Desktop:
Tip: switch to the "sandbox mode" before logging in the app:
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