atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Telecom Service & Providers RTN vs DNIS - what is the difference?

New to to this field, and just worked an issue where the carrier is stating a toll free number points to a ring to number, and not a DNIS. Can anyone provide any clarfication on what the difference is?

A Ring to Number is a real phone number. The toll-free number is not pointed to your circuit, but is pointed to the telephone number riding on your circuit (or regular phone lines).

DNIS is routed directly to your circuit. Over-simplified, but that's the difference.

To add a bit to that DNIS digits are given to you to ring a specific phone or group in your phone system. An example would be someone calls your sales group and dials and 800#. Your carrier may give you only the last 4 to route to your sales group or totally stip all numbers and give you the digits you want. It's all in how the numbers are delivered to your site. Only time DNIS is used is when your pipe terminates directly into your carriers switch. If I'm wrong on any of this one of our CO members will correct it.

Toll-free numbers are phantom numbers that must point to or "terminate" on any number of objects. Objects include a hard POTS line, a DID on an analog or PRI circuit, a straight T1 (with DNIS digits to follow) and perhaps other services that I'm overlooking as I type.

I've got a hard line at home. Anyone who knows it can obviously grab some dialtone and call me. But it's also true that I can buy a toll-free number that will terminate on that line. Now whether you call my locally published number or whether you call the toll-free, you'll still ring the same line at my house.

That's what the carrier mans by "a toll free number point[ing] to a ring number".