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Overlap Dialling

Discussion in '3CX Phone System - General' started by Pauliebrisbane, Dec 10, 2014.

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  1. Pauliebrisbane

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    Is there a way for 3CX to use overlap dialling internally?

    I have been testing the 3CX product using Snom phones and pressing an OK or SEND button or waiting for the inter-digit timeout doesn't feel as smooth as dialling the extension or PSTN number and the call being immediately transmitted when dial plan digits are matched.

    Can this be done either using 3CX or selecting a certain type of SIP handset?
     
  2. leejor

    leejor Well-Known Member

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    This generally involves the use of an internal, device, dialplan, "crafted" to handle the different digit combinations at your location. You'd have to see if your sets support this.
     
  3. Pauliebrisbane

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    Does this mean the dial plan is configured on each individual handset?

    and making a change to the 3CX dial plan would require and update on each handset?
     
  4. leejor

    leejor Well-Known Member

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    It would probably be a common dialplan (in the same office) uploaded to the sets based on the file name of the plan in the configuration file. At least that's how it's done in some Cisco sets. I have not used the model that you have, but someone else on the forum is probably familiar with it.

    Nothing would have to change in the 3CX outbound rules. The same digits would be sent from the set, it's just that once a match (within the set) is found, the digits would be sent immediately.
     
  5. Pauliebrisbane

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    Got it, Thanks.

    What I meant regarding a change on 3CX. If you created a new outbound rule with 5 digits for example, would this not need to be updated in the phone, so the phone knows how to match the new 5 digit outbound rule?
     
  6. leejor

    leejor Well-Known Member

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    Once you have established the outbound rules in 3CX, and all outside calls work as they should, then nothing would have to be changed unless there was a change to how outside calls were to be dialled, or restricted.
    With SIP, the digits from a set are sent as a "complete package" (except for individual digits sent after a call is established), so 3CX doesn't care what the set is doing before the digits are sent. It gets the whole digit string and "acts" on it.

    Some dialplans within a set/device can offer a lot of options. There are may examples of dialplans on-line, this is one from Cisco for some of it's devices. http://www.cisco.com/c/en/us/support/docs/collaboration-endpoints/spa901-1-line-ip-phone/108747-pqa-108747.html

    I'm not certain that it will apply to your sets but it gives you an idea of how it works.
     
  7. Pauliebrisbane

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    I found the overlap dialling option on the set and it somewhat works.

    I am testing with 3 digit extension numbers using extensions 110 an 111.

    When I dial 111 from 110 it rings immediately without pressing send. *Good

    When I dial 1.. then pause, from 110 it waits for more digits. *Good

    When I dial 11. then pause for a second, I get a "Not Found: unknown" message. xNot good.

    Is there an option in the 3CX system where it is matching the 11 and trying to process the digits early?
     
  8. leejor

    leejor Well-Known Member

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    Again, it won't be anything on 3CX itself. You could create an outbound rule for "11" and send it off to a non-existent destination, but you'd have to do that for a lot of mis-dialled numbers, so not really a viable solution. On the set there should be timers that determine how long it will wait between digits, and after the last digit, before sending all digits dialled so far off to 3Cx if they don't match a dial plan. However, there is only so much that you can do if someone is really slow when dialling a number.
     
  9. Pauliebrisbane

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    Can overlap be turned on from the 3CX end to facilitate overlap dialling on the endpoint?

    That way when the 11@x.x.x.x reaches the 3CX server is responds with "484 Address Incomplete", currently it is responding with "404 Not Found"
     
  10. lneblett

    lneblett Well-Known Member

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    3CX does not support overlap dialing as this is implemented at the endpoint (handset). It will need to be a combination of the handset's dial plan and the inter-digit timeout. The dial string is not sent to 3CX until such time as the user hits the send/dial button or waits for the inter-digit timeout to occur. Think of it as being akin to cell phone dialing. It is a 2 stage process where the user is not interactively dealing with DTMF tones with a CO switch, but rather inputting the number of interest first and then establishing a connection with the carrier.

    The issue you face is that 3CX simply processes the string sent to it by the endpoint. Unless it knows all possible (valid) dial strings, then it cannot return the incomplete address. Keep in mind that 3CX supports direct SIP dialing so 11@X.X.X.X is valid and will return a 404 response. Your phone apparently sent the "11"@x.x.x.x prior to the time the user was able to finish the entry and the inter-digit timeout kicked in; or the dial plan kicked in as it thinks that "11" is valid. 3CX is not processing the keystrokes dynamically.

    The outbound rules do not play a part in overlap as it merely processes what the system is given, determines if the string is applicable, makes the preprogrammed changes to the number when required and sends out the applicable route.
     
  11. Pauliebrisbane

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    Thanks for the answer, just what I was looking for.
    It would be nice if the server could look up all valid internal dial strings before responding with the 404.

    What is the most common process for dialling? inter-digit timeout or pressing OK or SEND?

    I may have a few of these sideways questions while I'm going through functional testing of the 3CX system.
     
  12. lneblett

    lneblett Well-Known Member

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    unless you would like to spend a lifetime learning the nuances of various manufacturer's dial plans, I usually use the cell phone analogy and suggest that they hit dial, send or "#" (which for some phones is the same as dial/send - a program feature). I then set the inter-digit timeout to 4 sec and let them know the significance of the setting.

    The latter is interesting as like in my house, the wife controls the remote. When I ask her to turn the channel, she will input the desired channel, but will wait for the inter-digit timeout rather than pushing enter so it will change immediately. It drives me nuts.
     
  13. craigreilly

    craigreilly Well-Known Member

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    Love that analogy Larry....
     
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