[VoIP] Berry 314A trunk test set (correction)

Sun Nov 4 17:14:00 CST 2007

YW.  Another thought Jerry... you ought to verify that the tone that 
DOES appear is on frequency, undistorted and continuous before investing 
much effort in a narrowly focused investigation. 

Steph

Jerry Petrizze wrote:
> Thanks Steph:  I will keep you posted.
> Jerry.
>
> ----- Original Message ----- 
> From: "Steph Kerman" <stfkerman at jps.net>
> To: "Voice Over IP Tandem for Analog Switches" <voip at ckts.info>
> Sent: Sunday, November 04, 2007 2:57 PM
> Subject: Re: [VoIP] Berry 314A trunk test set (correction)
>
>
>   
>> Sorry... 0.8V at the input, not 0.4V.
>>
>> =SK=
>>
>> Jerry Petrizze wrote:
>>     
>>> I feel the same way, why the beat note? But if there is two parallel
>>> processes going on which you would expect, is it possible that it is
>>> generating the same tone on both channels with just a slight time
>>> shift enough to create the beat.? Beats me!!!
>>>       
>> Perhaps there are two test points for examining the output of each tone
>> of the pair independently.  Otherwise it would be difficult to evaluate
>> the tone quality without complex instruments.
>>
>> Adding two phase shifted tones of the same frequency would not AFAIK
>> produce a beat note.  If the tone samples are fetched from EPROM it
>> seems unlikely a circuit failure could cause this to happen.
>>     
>>> It does exist in both MF and DTMF. However some of the keys sound
>>> normal, that's why I thought might be in the key pad logic.?
>>>       
>> I think the keypad is probably a single contact type rather than dual
>> contact type.  It's probably scanned by the CPU and interpreted in
>> firmware without any dedicated logic other than perhaps an input latch
>> or buffer.  Are the keys that do not work properly the same for both MF
>> and DTMF?
>>
>> Perhaps the contact resistance of the keys has risen to the point where
>> they do not deliver a valid logic level to the input port.  It sounds
>> like you have a scope.  I suggest inspecting the keypad terminals to see
>> whether solid logic 0 and 1 levels are appearing there and whether there
>> are static levels or whether it is scanned in a matrix.  Remember that
>> if the input device is TTL, it needs a logic 0 below 0.4V, which is very
>> close to ground, not 33% of Vcc as for CMOS.
>>     
>>> And yes without a road map your kind of lost. I will keep digging.Jerry
>>>       
>> Good luck!  "Write if you get work..."
>>
>> Steph
>>     
>>> ----- Original Message -----
>>> From: "Steph Kerman" <stfkerman at jps.net>
>>> To: "Voice Over IP Tandem for Analog Switches" <voip at ckts.info>
>>> Sent: Sunday, November 04, 2007 1:38 PM
>>> Subject: Re: [VoIP] Berry 314A trunk test set
>>>
>>>
>>>       
>>>> Very hard to say what the problem is without seeing a schematic.  Some
>>>> time back Paul doped out some superficial aspects of how it generates
>>>> tones.  IIRC it uses a digital technique based on parallel output shift
>>>> registers with weighted resistor values to perform a D/A function.
>>>> Presumably there would have to be 2 such implementations, with analog
>>>> summing otherwise the sample values would have to be summed....
>>>>         
> probably
>   
>>>> beyond what they would attempt with a 6800 family CPU.
>>>>
>>>> If only one tone is present, how can it be that you hear a beat note?
>>>> That seems contradictory.
>>>>
>>>> Is the problem evident on all keys in both MF and DTMF modes?  Specific
>>>> keys only?
>>>>
>>>> Steph
>>>>
>>>> Jerry Petrizze wrote:
>>>>
>>>>         
>>>>> Thank you anyway Paul since I did not have the Ops. manual for it
>>>>>           
> ether.
>   
>>>>> Steph: Everything seems to work on it except the tones are messed up.
>>>>> Like when you press the # one key in the MF mode you hear a beet note
>>>>> and one tone. If you look at the test point where the tones can be
>>>>> checked you just see one tone being generated. I believe the problem
>>>>> lies in the key pad interpolation circuitry.???
>>>>> Jerry P.
>>>>>
>>>>>
>>>>> ----- Original Message -----
>>>>> From: "Steph Kerman" <stfkerman at jps.net>
>>>>> To: "Voice Over IP Tandem for Analog Switches" <voip at ckts.info>
>>>>> Sent: Sunday, November 04, 2007 12:42 PM
>>>>> Subject: Re: [VoIP] Berry 314A trunk test set
>>>>>
>>>>>
>>>>>
>>>>>           
>>>>>> Same experience here.  What is the problem with it?
>>>>>>
>>>>>> =SK=
>>>>>>
>>>>>> Paul Wills wrote:
>>>>>>
>>>>>>
>>>>>>             
>>>>>>> Oops, I guess you meant documentation for maintenance. Good luck. I
>>>>>>>
>>>>>>>               
>>> was
>>>
>>>       
>>>>>>> never able to get anything like that out of Berry.
>>>>>>>
>>>>>>> PDW
>>>>>>>
>>>>>>> ----- Original Message -----
>>>>>>> From: "Jerry Petrizze" <t2600 at sbcglobal.net>
>>>>>>> To: "Voice Over IP Tandem for Analog Switches" <voip at ckts.info>
>>>>>>> Sent: Sunday, November 04, 2007 3:36 PM
>>>>>>> Subject: [VoIP] Berry 314A trunk test set
>>>>>>>
>>>>>>>
>>>>>>>               
>>>>>>>> Help!!! Needed, service documentation on a Berry 314A Trunk Test
>>>>>>>>                 
> Set.
>   
>>>>>>>> Thank you Jerry Petrizze
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>                 
>>>>>> _______________________________________________
>>>>>> VoIP mailing list
>>>>>> VoIP at ckts.info
>>>>>> http://lists.ckts.info/mailman/listinfo/voip
>>>>>> Project Web Page: http://www.ckts.info/
>>>>>>
>>>>>>
>>>>>>             
>>>>> _______________________________________________
>>>>> VoIP mailing list
>>>>> VoIP at ckts.info
>>>>> http://lists.ckts.info/mailman/listinfo/voip
>>>>> Project Web Page: http://www.ckts.info/
>>>>>
>>>>>
>>>>>
>>>>>           
>>>> _______________________________________________
>>>> VoIP mailing list
>>>> VoIP at ckts.info
>>>> http://lists.ckts.info/mailman/listinfo/voip
>>>> Project Web Page: http://www.ckts.info/
>>>>
>>>>         
>>> _______________________________________________
>>> VoIP mailing list
>>> VoIP at ckts.info
>>> http://lists.ckts.info/mailman/listinfo/voip
>>> Project Web Page: http://www.ckts.info/
>>>
>>>
>>>       
>> _______________________________________________
>> VoIP mailing list
>> VoIP at ckts.info
>> http://lists.ckts.info/mailman/listinfo/voip
>> Project Web Page: http://www.ckts.info/
>>     
>
> _______________________________________________
> VoIP mailing list
> VoIP at ckts.info
> http://lists.ckts.info/mailman/listinfo/voip
> Project Web Page: http://www.ckts.info/
>
>   