Blocking US Premium Rate Telephone Numbers (900 Numbers) in Lync Server
Let’s say that your company wants to prohibit dialing 900-numbers by its employees and visitors. The official name for numbers in this NPA within the North American Numbering Plan is “Premium-Rate Telephone Numbers”.
- Customizable Announcement which can either be a file or Text-to-Speech
- Customizable call forwarding action after the announcement is played
- A Monitoring Server CDR entry for the call so that you will know exactly which number the employee/visitor actually tried to call
Step 1. (Optional) Make Sure You Can Normalize 900 Numbers.
If you don’t already have a Normalization Rule in the Dial plan to cover these
numbers, then you can use this:
MATCH EXPRESSION: ^1?(900|976)([2-9]\d{2}\d{4})$
TRANSLATION EXPRESSION: +1$1$2
If you already have a sufficient rule, then skip this step.
Step 2. Create Announcement
New-CsAnnouncement -Parent service:ApplicationServer:lyncpool.catapultsystems.com -Name “Announce_USPremiumeRateNumbers” -TextToSpeechPrompt “We are sorry, but the Premium Rate Number you dialed is prohibited. If you need to reach this number, please notify your manager. Thank you.” -Language “en-US”
Step 3. Create Unassigned Number range(s)
New-CsUnassignedNumber -Identity “Range_USPremiumRate_900” -NumberRangeStart “+19000000000” -NumberRangeEnd “+19009999999” –AnnouncementService ApplicationServer:lyncpool.catapultsystems.com -AnnouncementName “Announce_USPremiumRateNumbers”
NOTES:
One of your additional options in the New-CsAnnouncement command is to add a SIP Address to forward the call to after the announcement has been played. If you have an Operator or Receptionist Response Group Workflow configured, then use its SIP address to send the call to.
For all practical purposes, you could start the number range at +1900200000 instead of +19000000000, since in the NANP, only 2-9 are valid first digits in the Nxx.
You might notice that my Normalization Rule match expression includes 976. Technically, 976 is not in use in the NANP, but premium numbers used to exist in that range, and it never hurts to block something that has no current legitimate use.
This is very helpful. Excellent post!
Connors
August 4, 2011 at 12:35 pm
Hey Brian,
Your excellent method of dealing with premium numbers inspired me to add that functionality to my Lync Dialing Rule Optimizer. See http://ucken.blogspot.com/2011/09/block-premium-rate-numbers-with-dialing.html
Cheers,
Ken
Ken Lasko
September 15, 2011 at 4:07 am
Thanks, Ken! I have used your tool before. You have done a great job with it.
rubartsunifiedcommunications
September 15, 2011 at 4:28 am