An extension is a group or user mailbox on your RingCentral account.

eg: Extension 101 for user A. Callers can then call the main number of your RingCentral account and dial extension 101 to reach particular user A.

ref:- https://support.ringcentral.com/s/article/5-10-User-Extension-Overview?language=en_US

In RingCentral's terminology, an account means a company(main number) , and an extension often means an user in a company. There can be multiple users or extensions.

ref: https://ringcentral-faq.readthedocs.io/en/latest/account/

A Direct Number is a phone number that can be dialed to connect directly to a User without going through the Operator or Auto-Receptionist. Direct numbers are simply phone numbers that tell the system where to send a call. They don't have the ability to dial out on their own, but can receive calls.

ref: https://community.ringcentral.com/ringcentral/topics/confused-about-adding-user-or-phone-or

https://support.ringcentral.com/s/article/5-10-Adding-Extension-Direct-Numbers-via-Web?language=en_US

Also you can check: https://support.ringcentral.com/s/article/9510?language=en_US

Hi Angelo,

Here are the answers for you:

You: We are developing an app which will use the RingCentral API to send/receive faxes (no voice, sms, ...)

Me: Login your developer account at https://developers.ringcentral.com and create a new app. Read this getting started doc for further instructions. Since your app is supposed to send and receive faxes, select the "Faxes" permission, and add the "WebhookSubscriptions" permission if you intend to implement webhook notifications for getting notified when there is an incoming fax. It's up to you to choose Webhook or PubNub notifications though.

You: We will have a pool of RingCentral fax numbers under one RingCentral account.

Me: Login your sandbox account at https://service.devtest.ringcentral.com (using your sandbox account main company number and password). Select the "Users" tab and click the "+ Add User" button. Follow the on-screen instruction to add a new user. Name the new user as e.g. "Fax station 1" and don't forget to add a direct number for that user. Add as many users as you want to have for your "fax pool". Note that sandbox account limit to max 4 users including the default admin user (i.e. the extension 101).

You: We signed up with RingCentral and started testing using the dev sandbox.

Me: Good start!

You: In this context, I am trying to understand the setup of accounts/users/extensions/direct numbers, caller id, etc..

Me: When you signup for a RingCentral developer account, you will have a RingCentral developer account and a RingCentral sandbox account (need activation to set a password) with an assigned main company number. The main company number is the user name for your sandbox account and you can login your sandbox account via https://service.devtest.ringcentral.com, where you can setup your account such as adding a user or changing default settings etc.

"User" and "extension" are the same thing. When talking about a use case, we normally use "user", when talking about technical/programming, we normally use "extension". So when you add a new user, you are adding a new extension to your account.

A user can have it's own phone number (a direct number) so that people can dial that number directly. Otherwise, they have to dial the main company number followed by the * and the extension number (e.g. 16501234567*102)

A caller id is the phone number that will be seen by a callee's when you make a call.

You: So we have a Main Number which also seems to be our account login username - is this normal ?

Me: Yes, and as explained above, this is the user name to login your sandbox account. NOT your developer account.

You: When sending faxes, we will pick a number from the pool of RingCentral fax numbers in our account and send a fax FROM that number to an external fax number.

How do we setup the multiple fax numbers that we will need ?

Me: When you send a fax from any extension under your account, by default the "from" number is your main company number. You cannot specify the from number (see the sample code).

What you want to do is possible only if you setup your account as I discussed above (the "Fax station 1", "Fax station 2" etc. as your users). Then set the Fax settings of each fax station from the Outbound Calls/Faxes setting dialog. Scroll down to set the direct number of the user to be the "Fax number".

To select a fax from your "Fax pool", you have to implement your logic to select a "fax station #", then login the app with that "fax station" (user) login credentials then send your fax.

You: The users/extensions/direct numbers, caller id, etc.. is not very clear to me.

Me: Already explained above