Pardon my ignorance, but what exactly is the difference between DID and DNIS? I've programmed many PRI's and used DID info, but I notice many systems (like Toshiba) are looking for DNIS information or ask you to choose between the two. Thanks in advance.

Purpose is the same, but DID is actually digits number sent by provider to switch and DNIS is a Digital Number Identification Servises that comes in special format that has to be recognized by switch and translated to your numbering plan. Exapmple is Mitel: At the begining of the T1 capability it recognized services only from AT&T and MCI nobody else. DID was available only on DID Trunk card not T1. And some system still gives you a choice what kind of T1 card to use: DS1 or PRI. DS1 works only with DNIS but PRI uses DID.

I believe in Mitel, you can use DID or DNIS on T1. That's what I was taught in Light 15/16 class 11 years or so ago!
DNIS was thought to be more useful in an inbound marketing situation, while DID was more useful when many people in an organization needed their own phone number. Only real difference I can see is DNIS gives you the WHOLE dialed number, while DID gives you 3-7 digits, digits normally specified when DID is ordered. John C.

My dear John,
You are right in Lightware 15/16 was a PRI ISDN capability but not from 1001 -1004. It was only T1 DS1. But it was discriptor T1/DID available for DNIS service and T1/E&M for matching numbering plan.

Where's our switch guys? From my NODAL days. DNIS is where you dial a number and the desired digits are sent to the PBX and ring the extension. DID the trunk is dedicate to a certain extension/group. On a DNIS trunk I could access the trunk (from a test position) and dial any extension in the PBX, if I wanted. On a DID I would put ringing voltage on the trunk and it went to the specific station/group assigned to that trunk.

Hi justbill,
I remember testing DID on Merlin Legend by clipping my buttset on the DTMF DID Trunk T&R and dial digits and dedicated Extension was ringing. Yes, there is DID trunk and DID number which can be any number of didgits sent to dedicated point. As far as my knowlage goes DNIS is a string send by provider which includes some codes together with numbers that supposed to mean something to switch for proper interpretings and pointing like, for example, *4*3333# that can be like pause, 3 gitits ext# follow by actual number. 333.

Sorry Bill...busy day..but you guys got it covered

Set us straight Anthony. vad60, there are no special codes in DNIS digits that I know for sure. I'm pretty sure I'm right on the DID too. Trunks with DNIS were set up like any trunk, wink, immediate, DT, whatever the customer wanted, you got your signal from the customer switch and dumped your digits, usually 3 or 4, but whatever the customer ordered. DID trunks we didn't dump digits, just rang out on the trunk.

DIDs are a dedicated range of digits..for example you can buy a block of 200 from the carrier. Example 210-555-2000 through 210-555-2199. Any analog or digital DID trunk that is seized inbound that pulses the prescribed amount of digits (3-7 digits) will be presented to the PBX in a manner to be interpreted by the customer premise equipment. If they are sending 4 digits in the previous example and the first number was dialed the PBX would see 2000. A DID routing table would tell the system where to route the call to internally. A DNIS number would be outside the DID range. Say for instance the customer had the previous mention DID block but was porting a number that was 210-555-9933. The DNIS would probably be 9933. Still presented and routed as a DID but outside the range. No special codes.

Thanks for the explanation RBF.

Edit: A little brain work would have told me that on the DID=direct inward dialing..some days. :scratch:

So what were the ones called we just rang out on and it went to a preset extension or group?

No problem.

The ones you rang out that went to a dedicated group was either private CO line groups outside the main group or if you dial any number not assigned it will go to a dedicated point..usually the operator. I just had a customer that was getting spammed by an Awards Claim company promising a free Ford truck by calling back the 800 number and giving a claim number. Any unassigned number was ringing the operator. They had 400 DIDs and roughly half were unassigned. She was getting probably 200 calls a day. I took the DID table and sent all unassigned DIDs to a mailbox that says "Quit calling you worthless spammer."

RBF,
Thank you very much!

Justbill, You have it right. DID (direct inward dial) just hit a trunk group to a pbx and the pbx would complete the routing. The caller could dial digits if they knew an extension numer once they hit the pbx. The deal is, the number of DID's can be more than the number of actual trunks terminated to the pbx. Hence a block 100 DID's don't need 100 trunks to teminate to.

DNIS (dialed number identification service) dumps the last 3 or 4 digits of the DID automatically, although any digits can be sent.

I don't recall ever seeing anything other than digits (0-9) being sent as DNIS. Although I've seen * and # sent as the start and stop to some pbx's that use FG-D protocal with DTMF.

How would the PBX know where to dial unless it received identifier digits? The only digits dialed by the caller is the direct number..not any numbers after the PBX answers. What you are describing is DISA or auto attendant where the caller dials digits after answer to direct the call.

Ya know I've been doing google searches for a good down to earth type explanation and what you've said is about what I've found on the searches. DNIS is a DID that dumps digits after connected to the customer switch. I think I'm going to quit now, because I thought I knew and now I know I don't know what I thought I knew, but tomorrow is a new day so maybe I'll know tomorrow who knew what today.

:rofl: RBF, HaHa, If I did something like that the next call would be the CEO of the company mis-dialing one digit and hitting the smart-ass recording!

All DID and DNIS calls are routed after the PBX answers. The CO is pulsing a DID number or a DNIS number on a trunk that accepts inbound digits. The PBX then directs based upon info received.

Any digits can be sent by the carrier as DNIS, not just the last digit of the DID. I didn't mean any random digits. For example: you are using 3 digit dnis. Two of your DID's end's with 123. This causes a conflict with your routing. So you have the carrier send a different dnis number on one of the DID's.

Right. In my first statement it said DNIS was sent outside the DID block numbers. They have to tell you what DNIS they are sending since you already know what your established DID range would be. It does have to be different.

I got the OK from the big guys. At first I set it up to hit a mailbox that blind transfered to the 800 number. So everytime they called my customer it called them back on their 800 number. After scratching heads we figured that might be considered harrassment so we just went with the announce mailbox and hangup.

Not to argue.

I will try to make this simple for Kevhawk13.

DID is the digits that come in as RBF stated earlier. When someone calls 918-555-1212 then the carrier switch is set to send X digits. in this case we will say 4. It sends 1212 to the phone switch on the customer location. The phone switch then has a routing table that says digits 1212 goes to extension 323 or what ever your system is set for.

ANI. on a e&m T1 trunk is the callerid number only information. This is why when a carrier tells you that he is sending *DNIS*ANI* or *ANI*DNIS* this means it will send *1212*4055551212* or *4055551212*1212* This is so that you will get callerid number. Callerid name is not on E&M wink start trunks.

Having setup many of these in the DMS class 5 phone swithes on T1. I have not ever tested this on an analog DID though. Around Oklahoma they are not very common.

Several people consider the DID and ANI on a PRI as well. However it is the basically the same thing it is not exactly the same.

On a PRI the Call information is sent over a D channel. This type of service does support Callerid Name and Number. However it is not considered ANI on this type of service. But the DID portion is still considered DID just sent differnet format.

Hope this helps.

Brian

"On a PRI the Call information is sent over a D channel. This type of service does support Callerid Name and Number."

True it is sent over a D channel. I install NI2 protocol PRIs almost everyday that do deliver name and number and I receive DNIS digits also. They are treated as DIDs. DNIS delivered on an analog T1 is considered ANI to most PBXs I have been associated with.

You can have DNIS on PRIs without DID numbers but they still must be treated as DIDs and translated.

Sorry RBF.

Typed the wrong acronym. You are correct ANI. I have edited my post.

Thought the right one typed the wrong one.

Brian, that pretty much sums it up. DID digits match the last digits (2-7 digits) dialed exactly, where DNIS digits can be whatever is requested of the carrier. For example, the customer's sales department's local number is 578-832-8700. When local callers dial this number, 8700 is sent as DID digits.

When someone from outside of the area dials the company's toll-free number (800-832-8700), the long distance carrier doesn't simply send "8700" again. The customer needs to be able to track the calls on an originating basis (local or out-of-area).

With DNIS, calls to the toll-free 8700 number from San Diego might send 9991 as DNIS digits; Chicago would be 9992 and so on. Different DNIS digits are being sent based upon the dialed number to allow the advertiser to track the originating area (and TV channel) generating the sales lead.

The true answer is that DID digits are fixed digits sent that are tied to the dialed local number. DNIS digits can be manipulated by interexchange carriers so that they don't have to match the dialed number at all. DNIS is the way of the times since it offers much more flexibility.

You can send me "5974481" and my PBX automatically knows that you really need extension "25".

That is true ed.

Just for him to keep in mind that in most cases a 800 number is pointed to a local DID number.

Here is another example for him.

Lets say you have 2 number coming in 4056394115 and 4057214115. Your switch is setup for 4 digits. This would mean you would have 2 phone numbers setup to send 4115 to your switch.

In this case you would request the carrier to send different digits to you for one of the phone numbers.

You would leave 4056394115 as a DID sending 4115.

You would request that 4057214115 send DNIS 9981 to your switch.

This way your switch would know that one number routes to one extension and the other number routes to another extension.

Or in what ed is saying you could set both numbers to route to the same extension. But the 800 number is pointed at 4056394115 and the main phone number to the business is 4057214115. This way you could tell how many 800 calls you get verse how many local calls you get.

Basically as Ed stated above. They both work the same. Telco sends x DID digits to phone system. Telco sends X DNIS digits to phone system.

The only real difference is if the telco is converting the sending digits or just sending the last X number of digits of the phone number.

Brian.

Gentlemen,
Thanks for the info!

"True it is sent over a D channel. I install NI2 protocol PRIs almost everyday that do deliver name and number and I receive DNIS digits also. They are treated as DIDs. DNIS delivered on an analog T1 is considered ANI to most PBXs I have been associated with.


So RBF.....

The DNIS on PRI channel D is sent over NI2 is treated as DID while DNIS on T1 is considered ANI by the PBX.

And you guys think the GCs talk funny. :confused:

Don't you have a computer to reboot? :rofl:

Actually, I think I need a beer or two after reading this thread. It does answer some questions I've had on DID, but never asked. Thanks everyone for that. :-)

The beer or two thing has always worked for me.

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Dnis question for lucent Legend

WE have a merlin Legend with a t-1 card and a full voice t-1

I have one 800# with DNIS 145 pointing to extension 145.

I have a national 800 # with unique routing hitting 3 differnt physical office locations based on area code origination.one of the routing destinations is the 800# with DNIS 145

I have been advised that calls off the national 800 must have a differnet DNIS other than 145. I Assume the carrier can send these to my t-1,but insert 245 rather than 145.

Is it possible to have the legend translate the dnis string of 245 to 145 at the switch? The objective it to get the call on ext 145 on the inside. Waht is the best way to handle this.

How about opening a new topic in the Avaya forum instead of attaching to a nearly 3 year old topic. Thanks.