Analog extension passes DTMF perfectly but not Digital telephones

[adc110]

Ok - this issues is not necessarily an IP Office issue however a translation issue of some sort so be prepared for this one!

I have remote Safetran (a device that allows us to dial into it remotely and access a radio for communication). This device (Safetran) does not play nicely when you dial it from anything digital/IP but analog works. When you attempt to send it a 2 digit command it simply does not respond from digital/ip devices. Here are my tests:

Telecommunications System: IP Office 500 V2 9.1.x with dual PRI cards and one analog POTS

1. Dial out over PRI or SIP or POTS trunks using a digital extension (9508 or 1416) the saftran cannot process my DTMF digits (only 2 digits and could be 03, or 15, or any combination)

2. Dial out over PRI or SIP or PTS trunks using SIP or IP extension the safetran cannot process my DTMF digits

3. Using a hosting/cloud based SIP telephone extension (non avaya related) safetran cannot process my DTMF digits

4. However - if I use a cell phone or if I hook my buttset or analaog phone to the IP Office I can interact with the safetran all day long with no issue.

5. If I call from my home analog phone it works perfectly as well

This all being said - how would anyone think that an analog extension behind an IP Office would behave any differently than a digital when passing out DTMF using any type of media (SIP, PRI, POTS), etc...

I am not sure if that "actual" device can process signals differently depending on type?

 

[IPGuru]

have you tried connecting a test but to the safetrans connection & seeing if the IPO is actually sending DTMF when accessed from a digital handset?

if so you need to use a ziad or similar to see if the digits being received are valid *& not corrupt

This all being said - how would anyone think that an analog extension behind an IP Office would behave any differently than a digital when passing out DTMF using any type of media (SIP, PRI, POTS), etc...

an analog device will be directly inserting DTMF into the open speech connection, with a digital/ip handset the phone sends a message to the IP office to play the DTMF tone which is then generated by the IPO.

there was an issue with early DS30/12 modules that would cause them to stop sending DTMF if they ha not been correctly upgraded via a interim build but this should not be affecting a V9.1 system


Do things on the cheap & it will cost you dear

 

[budbyrd]

From experiance with paging devices that use DTMF, the IPO sends a very short DTMF burst that some recieving devices don't like. You can hold the button down on a digital set and it sounds like you are geting a steady tone, but that isn't what it is sending.

Dermis and feline can be divorced by manifold methods.*
*(Disclaimer for all advise given)--'Version Dependent'

 

[Billxx]

I agree with the previous posting.

I would say that the trouble is in your Safetran and not the PBX.

The primary difference between an Analog Telephone and a Digital Telephone is the actual Duration of the DTMF.

A Digital Telephone just sends out a very short burst of DTMF. (This can be adjusted in the PBX for Analog POTS)

Whereas an Analog Telephone will send out DTMF for as long as you hold down a keypad button.

So, keep in mind that the PBX is designed to work with Telecom Service Providers and not every DTMF controlled product out there.

Possible solutions:
See if the Safetran is programmable to a shorter burst of DTMF.
Lenthen the DTMF "ON" time in the PBX for your Analog POTS Line. (May or may not solve the trouble)

 

[adc110]

Thanks for all the comments! It does make more sense. Billxx when you mention "A Digital Telephone just sends out a very short burst of DTMF. (This can be adjusted in the PBX for Analog POTS)" are you suggesting that I may be able to make adjustments to the POTS line that I have in the system to see if and adjustment may allow our digital phone to get appropriate DTMF to the safetran?

 

[Billxx]

Yes you can try.

I do stand to be corrected on one item.
The Digital Telephone itself does not generate the DTMF, it is done by the PBX.

Go to Line / Select the Analog Line / Analogue Options / DTMF / On (ms) and set it to 255 (max).
Hopefully that will solve the problem.

From the Manual:
DTMF These settings are used for DTMF dialing.
On: Default = 40ms. Range = 0 to 255ms. The width (DURATION) of the on pulses generated during DTMF dialing.
Off: Default = 60ms. Range = 0 to 255ms. The width of the off pulses generated during DTMF dialing.