External Phone Numbers




External Phone Numbers allow you to attach an extension to an outbound phone number. For example, you can take the 800 directory service number (1-800-555-1212) and attach it to an internal extension of 411 as shown in the example below.

External phone number list

You can also create an external phone number and use it as a failover for menus, users and groups. For example, you can set your mobile phone number as an external address, and if someone calls your extension and there is no answer, the call can then be sent to your mobile phone.

Note: Please be aware that standard PSTN calling rates still apply.


Creating an External Phone Number:

New external phone number

  1. Navigate to the "Resources" page in the admin portal and click "Create New Resource"
  2. From the list of resources choose "External Phone Number" > "Create a new External Phone Number"
  3. Enter the telephone number to route to starting with 1, then area code, and number
  4. Choose the billing method for this external phone number. This choice comes down to the question, do you want to be billed for calls to this external phone number, or do you want the caller to be billed? The answer to this question determines whether or not you want to bill the authenticated caller, or bill a user in your account.

    Choose a user if:

    • Anyone calling from outside the OnSIP network will be routed to this number, this includes callers from the PSTN
    • The number is related to calls for a specific user and you want charges to show up under this user's CDR reports
    • Another destination (like a group or an ACD queue) will fail over to this external number

    Choose authenticated caller if:

    • Only people calling from a device that can authenticate with OnSIP, e.g. callers in your organization calling from their SIP phones, will be routed to the external number
    • You would like the caller to be billed for calls going out to the external phone number

    Note: If the authenticated caller is chosen as the billing user and the caller can not authenticate with OnSIP, then the call will be hung up.


Why does my "External Phone Number Details" say "Restricted"?

Since calls to your external phone number will eventually end up on the PSTN, OnSIP needs to bill normal PSTN rates for these calls. If you have chosen "Authenticated Caller" then calls made to this external phone number will only be passed on to the PSTN from SIP phones that can authenticate with OnSIP. That is any phone configured with the User Address credentials that can normally make PSTN calls. In this case that phone (and account) is the one that will be billed for the phone call. Additionally, if a phone on the PSTN calls into your OnSIP PBX and gets transferred to an external phone number (e.g. someone dialing 411 from at an Auto Attendant) the call will be rejected and hung up. This mechanism prevents you from being billed for calls that you did not intend to be answered.

In order to circumvent this behavior, and for all calls from an external phone number to be completed, choose a user to bill the calls to in the "Bill To" section of the External Phone Number Details.

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