[VoIP] Dial Pulse converter specifications

[Steph Kerman]

Ken,

The proposal is to create unTeltone unconverters that do DP->TT rather 
than TT->DP.  The DP counting and DTMF tone generation can be 
accomplished with a small microcontroller such as a PIC family member.  
The loop interface of course requires discrete components.  There is no 
need to meet FCC requirement since it will be used in private networks, 
not directly on the PSTN.

Steph

kemartinatsnetnet wrote:
> Steph,
>
> So you are basically saying to create something like the Teltone 
> converters but from the ground up.
>
> What are you thinking about?  Something like a discrete DTMF chip or 
> build the DTMF front end ground up and control the unit by something 
> like a Parallax Basic Stamp chip (compiled basic or 'C') which should 
> be able to store the decoded DTMF and directly control a relay and do 
> the dial-pulsing. This could get complex if you have to take into 
> account incoming digit timing, how long to wait for additional 
> digits, loop supervision, forward disconnect, etc.  Plus the actual 
> hardware design.
>
> Would this need to meet current FCC connection requirements?
>
> Questions, questions.
>
> Ken
>
>
> --- In singingwires at yahoogroups.com, Steph Kerman <stfkerman at ...> 
> wrote:
>   
>> No.  It does not prevent dial pulses from reaching the TT device or 
>> line.  Some ATAs see each dial pulse as a disconnect and reseizure.
>>
>> If the ATA recognized DP correctly, a potential cause of double 
>>     
> dialing, 
>   
>> you would not need the converter.
>>
>> SK
>>
>> Nathaniel D. Watson wrote:
>>     
>>> I do not own one, so I do not know much about it, but would one 
>>>       
> of the
>   
>>> converters sold by Mike Sandman not serve this purpose? (Provided 
>>>       
> that the
>   
>>> ATA strictly requires TT dialing, otherwise you'd end up with 
>>>       
> double-dialing
>   
>>> of each digit). His catalog number for the device is: CID6K.
>>>
>>> Nathan
>>>
>>>
>>>
>>>
>>> on 1/3/07 9:40 AM, Steph Kerman at stfkerman at ... wrote:
>>>
>>>   
>>>       
>>>> More loop supervision?  What do you mean?
>>>>
>>>> 1)  It needs to connect into the loop.  A design was published 
>>>>         
> that
>   
>>>> installed in a phone and connected directly to the dial pulse 
>>>>         
> contacts.
>   
>>>> This is not a suitable configuration.
>>>>
>>>> 2)  It needs to provide a DC current path during the dial pulse 
>>>>         
> break
>   
>>>> intervals to prevent the downstream device from seeing each 
>>>>         
> pulse as a
>   
>>>> disconnect. 
>>>>
>>>> 3)  It should support 10 PPS to 20 PPS operation.  20 PPS 
>>>>         
> operation is
>   
>>>> not supported on some modern exchanges that support 10 PPS 
>>>>         
> operation.
>   
>>>> Supporting 20 PPS operation would make it possible to use 20 PPS 
>>>>         
> dials
>   
>>>> both in these environments and in SXS environments equipped with 
>>>>         
> TT
>   
>>>> converters.
>>>>
>>>> 4)  It should work with real-world dial pulses that have pulse
>>>> characteristics at the extremes of the readjustment limits 
>>>>         
> published by
>   
>>>> the Bell System.  This includes ratio, average and instantaneous 
>>>>         
> speed
>   
>>>> and contact bounce.
>>>>
>>>> 5)  A goal would be to make it loop powered, but that's not an 
>>>>         
> absolute
>   
>>>> necessity.  It could be designed to only consume power during 
>>>>         
> pulse
>   
>>>> conversion, so that battery operation could be achieved with 
>>>>         
> very long
>   
>>>> battery life.
>>>>
>>>> 6)  It should use readily available commercial electronic 
>>>>         
> components: no
>   
>>>> antique switching equipment relays with pure unobtainium 
>>>>         
> contacts.
>   
>>>> 7)  A printed circuit board would be designed and procured from a
>>>> commercial prototype board house to permit easy assembly without 
>>>>         
> random
>   
>>>> hand wiring.
>>>>
>>>> Steph
>>>>
>>>> john jones wrote:
>>>>     
>>>>         
>>>>> Since so many VoIP ATA's don't support DP dialing,
>>>>> there has been a suggestion to construct a TT to DP
>>>>> converter.
>>>>>
>>>>> I'd like to start collecting specifications of what
>>>>> this device needs to do.
>>>>>
>>>>> I expect that on the FXS side, it ought to perform in
>>>>> ways similar to the teltone converters often installed
>>>>> between Linefinders and the 1st selector although I
>>>>> imagine that more loop supervision is required.
>>>>>
>>>>> Let's get a dialog going on this.
>>>>>
>>>>> Thanks!
>>>>>
>>>>> John
>>>>>   
>>>>>       
>>>>>           
>>>
>>>
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