Overview

In order to keep a current and active inventory of phone numbers, Skyetel has to know which numbers are currently in service and which numbers have ported out. We need this information so that we can offer cool features like SMS and accurately bill our customers for their usage. 

Turns out, this is much easier said than done. Most companies keep track of their inventory by matching them to what their upstream providers show and just assuming their customers are keeping an active list of phone numbers that they've sold and are in use. We found that to be wholly inadequate and so we a designed mechanism where we keep track of our customers inventory for them in an easy to use way. 

How it works

Phone Number State works very intuitively - we simply call all of the phone numbers in our inventory if they have not received any traffic for 7 days. These calls are then caught by our SIP Routers and redirected to a special service that validates the call. If the call goes through normally, we mark the phone number as Active, if not, we mark it as Warning. If another 7 days go by without active calls, we try the test again. This time, if the call does not come through, we mark it as Error. 

Once a phone number has been marked as being in an Error state, a Skyetel engineer will review the number to see why we have it listed in our inventory. This process may take several days - we prioritize this kind of support below customers who submit tickets. 

How it looks

...

...

• Green - Your phone number has received traffic in the last 7 days
• Red - Your phone number has not received traffic in 14 days, and has failed test calls
• Orange - Your phone number has not received traffic in 7 days, and has failed one test call
• Empty/Grey - Your phone number has not received any traffic and we have not tested it yet

Error State

A phone number may be in an Error state for a few reasons:

• The number ported out of our network
• The number was returned to the PSTN without your knowledge (this is extremely rare)
• A number has not completed the Port In process, and is sitting in our Inventory in the days leading up to the port
• A number was accidentally transposed or had a typo in it 
• Other unusual reasons not listed here

Whenever a phone number is in the Error state, and we determine that it is not because of a Port In or PSTN error, we will mark the number for removal from our Inventory. If the number has ported away, you may be charged Port Out fees for the numbers we remove. 

Phone Calls

In order to test all of our numbers, we place a call to all of them. This call is free and will not show up on your CDRs or hit your PBX. However, because we are programmatically calling all of our numbers (a Skyetel engineer is not manually calling them), it is possible for us to call numbers that are listed in our Inventory that are not actually on the Skyetel Network. This is the case for numbers that have Ported Out, or have not yet finished Porting In. 

If this happens, the caller will hear a robot voice say "Testing Testing" and then hang up. If they call that number back, they will hear the following recording TestingNumber.wav

"The number you have dialed is part of automated phone service testing system that verifies that your phone service is working correctly. We apologize if you have a call from this number in error"

...