Unlike plain old telephone service, the ATA that links your home phone to the VoIP provider must know when you’re done before attempting to dial the numbers you’ve entered. Therefore, all ATAs have a setting called “Dial Plan” (or somethings Dial String) in order to analyze the digits typed, and make the appropriate decisions for dialing.

By default, an ATA will simply wait until the user doesn’t add new numbers for a few seconds, and then dial that. There’s a few problems with that:

• Always have to wait for that timeout period before actually making the call.
• If you make a pause mid-typing, it will try to dial that, and then you have to start over.
• All special numbers (311, 511, 811…) won’t work. Even 911 might not work if the VoIP provider did not implement it.

For all those reasons, I have spent some time to create a very practical dial plan. It’s particularly helpful for residents of Quebec (and Montreal) because certain services (x-1-1) are rerouted to the actual phone number of these services. Therefore, with this dial plan, I can reach:

• 311: Montreal City
• 411: A free phone directory service (800-555-1212)
• 511: Quebec 511 line (transports)
• 811: Health Line (Info-Santé)

Note that I’m using this with FreePhoneLine, so they already cover the 911 services. If your provider doesn’t link emergency services to 911, you can add a section to call your local emergency services. To get the number, just call your local police station at their non-emergency line, and simply ask for a number to reach them from “internet telephone” or something. They might have to search for it as it is quite unusual.

{911|<311=5148720311>|<411=18005551212>|<511=18883550511>|<811=18003613977>|x11|*xx|[2-9]xxxxxxxxx|1xxxxxxxxxx|011xxxxxxxxxxxx.|^1900x.|^1976x.}

(911S0|<311:5148720311>S0|<411:18005551212>S0|<511:18883550511>S0|<811:18003613977>S0|x11S0|*xxS0|[2-9]xxxxxxxxxS0|1xxxxxxxxxxS0|011xxxxxxxxxxxx.|1900x.!|1976x.!)

Tags: analog telephone adapter, ata, dial plan, dial string, freephoneline, grandstream, Howto, linksys, phone, voip

This entry was posted on Friday, August 20th, 2010 at 23:15 and is filed under Howto. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.