Multiple concurrent calls

Hi All,

How do Hosted PBX Providers handle multiple concurrent calls on a single number alloted to their client?

Many Companies are offering a Hosted PBX solution where they give you a single number for your customers can call you. The numbers allotted are Mobile Phone numbers and the companies are even ready to handover the SIM card to you if you no longer want to continue.

Since these are Wireless Solutions (GSM/CDMA) and not wired solutions like ISDN, I was wondering how do the system manage when say 10 people call the same cellphone number at the same time ? I am sure they do not get a busy tone.

Do they immediately transfer all the incoming calls to a VOIP extension ? how much time does this transfer take ? and how many calls can be handled in a minute in this manner ??