Typically when you set an external number, you want an outside agency to receive calls as though they are an internal part of your organization or you have individuals in the field who need to receive calls, such as a sales or repair team. There are two ways of doing this each with unique advantages.
User has an External Number and SIP Phone
If the individual in question will be using a SIP phone in addition to the external phone, you may want to set a unique extension to that external number. This way, if you already have an auto attendant with extensions set up, people can dial your number, followed by the extension for an employee, and immediately be directed to that cell number, regardless of whether or not your employee also has a SIP phone. If you have a distributed work force with duties either in the office or in the field, this may be the best solution for your company.
User has an External Number Only
If you are setting up an external phone number for someone who will not be using a sip phone, you can simply create a user, set their inbound call preferences to ring any amount of seconds then send to an external number. If there is no phone registered, then the system will automatically follow the “then send to:” rules you assign. This is easy in that it gives the administrator a name associated with the number as opposed to having to recall which external phone number ties to each person specifically using just extensions.
Additional Tip for Users Utilizing both External Numbers and SIP Phones
Let’s assume you’ve created the SIP account already. Create a user and name it “Name Cell” and select an extension. You may find it easier to give everyone’s Cell User extension a unique prefix. For example the system default extensions are 7XXX, for cells why not use 6XXX? This way to dial someone’s desk phone, you would hit 7001, but to reach his or her cell you would dial 6001. From the Inbound Call Preferences pane select your ring time and for “then send to:” enter your user’s cell phone.
Temporary Out of the Office Forwarding
If you are going to be out of the office for a short while, you can also set up your individual SIP phone to forward to an external number. Refer to your manufacturer’s documentation for instructions relevant to your device. Remember, for it to function properly you must add the external number into your resources list.