[VoIP] WE 2500 question

Wed Mar 14 14:42:58 CST 2007

Fine. 

First let's define terms.  A plug is a male connector attached to the 
end of a cord.  A jack is a female connector, usually mounted stationary 
mounted to a surface or in a piece of equipment

Standard double plug-ended modular cords inherently reverse the polarity 
of the line.  This is because they are flat, have a ridge along one 
face, and the plugs are installed with the latching key on the same side 
as the ridge.   This reversal is normally compensated by the fact that 
the wall jack and jack in the base of the phone are different, with 
oppositely color coded contacts.  Because of this inherent reversal, if 
you connect a standard flat line cord between 2 wall jacks or 2 
telephone set base jacks you will find continuity between red at one end 
and green at the other, rather than between identical colors as you 
probably would expect.

For this reason, if you plug your phone into one jack of the "T" and use 
a second line cord to patch the second jack of the "T" to the wall, this 
will reverse the polarity fed to the phone.  The male end of the "T" 
which normally would be inserted in a wall jack is unused when using a 
"T" to reverse polarity this way.

Steph

Jayson Smith wrote:
> Hi,
> Yes, we've got lots of those. We usually get them at Radio Shack. They've
> got them now with two, three, four, or maybe even more jacks. I think I have
> both the type that is an adaptor block, and also the type that has the phone
> jacks at the other end of a long phone cord, thus my "extension" reference.
> Jayson.
>
> ----- Original Message ----- 
> From: "Steph Kerman" <stfkerman at jps.net>
> To: "Voice Over IP Tandem for Analog Switches" <voip at ckts.info>
> Cc: "Jayson Smith" <ratguy at bellsouth.net>
> Sent: Wednesday, March 14, 2007 4:27 PM
> Subject: Re: [VoIP] WE 2500 question
>
>
>   
>> There is a widely available adapter that you plug into an existing jack
>> and which has 2 jacks on the back into which 2 devices can be plugged
>> instead of the single device that could have been plugged into the
>> original jack.  Most people call it a "T" or "tee".  Do you have one?
>> "duplex/extension" means anything and nothing to me.
>>
>> Steph
>>
>> Jayson Smith wrote:
>>     
>>> Hi,
>>> Do you mean, like a duplex/extension/whatever you call those? The phone
>>>       
> does
>   
>>> have a modular jack.
>>> Jayson.
>>>
>>> ----- Original Message ----- 
>>> From: "Steph Kerman" <stfkerman at jps.net>
>>> To: "Jayson Smith" <ratguy at bellsouth.net>; "Voice Over IP Tandem for
>>>       
> Analog
>   
>>> Switches" <voip at ckts.info>
>>> Sent: Wednesday, March 14, 2007 4:18 PM
>>> Subject: Re: [VoIP] WE 2500 question
>>>
>>>
>>>
>>>       
>>>> Does the phone have a modular plug?
>>>>
>>>> Do you have a modular "T" for connecting 2 phones to the same jack?
>>>>
>>>> Steph
>>>>
>>>> Jayson Smith wrote:
>>>>
>>>>         
>>>>> Hi,
>>>>> Unfortunately, being blind, I'm not in a good position to measure
>>>>>           
> those
>   
>>>>> voltages. I just tried several phone cords, including the one shipped
>>>>>
>>>>>           
>>> with
>>>
>>>       
>>>>> the phone, on my unused BPA-410. None worked. I like the phone, it's
>>>>>
>>>>>           
>>> exactly
>>>
>>>       
>>>>> what I wanted, I just wish it'd work on my IAXy!
>>>>> Jayson.
>>>>>
>>>>> ----- Original Message ----- 
>>>>> From: "Martin Harriss" <martin at Princeton.EDU>
>>>>> To: "Jayson Smith" <ratguy at bellsouth.net>; "Voice Over IP Tandem for
>>>>>
>>>>>           
>>> Analog
>>>
>>>       
>>>>> Switches" <voip at ckts.info>
>>>>> Sent: Wednesday, March 14, 2007 3:05 PM
>>>>> Subject: Re: [VoIP] WE 2500 question
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>           
>>>>>> Jayson Smith wrote:
>>>>>>
>>>>>>
>>>>>>             
>>>>>>> Hello,
>>>>>>> So is this saying, I'd need to somehow get a phone cord with some
>>>>>>>
>>>>>>>               
>>> wires
>>>
>>>       
>>>>>>> reversed?  I'll try the phone cord that came with the thing. For
>>>>>>>               
> those
>   
>>>>>>> curious people among you, here's a recording of what I'm getting.
>>>>>>> http://www.bluegrasspals.com/2500.wav
>>>>>>> Jayson.
>>>>>>>
>>>>>>>
>>>>>>>               
>>>>>> Jayson,
>>>>>>
>>>>>> Are you in a position to measure the off-hook and on-hook voltage for
>>>>>> this phone/ATA combination?  (Or have someone else do it for you?)
>>>>>>             
> It
>   
>>>>>> would also be interesting to measure the off-hook voltage both with
>>>>>>             
> and
>   
>>>>>> without one of the dial keys pressed.  I wonder if the ATA is putting
>>>>>> out enough voltage (especially when the phone is off-hook) to run the
>>>>>> dial pad.
>>>>>>
>>>>>> I seem to recall that when you pressed a key on those old dial pads
>>>>>>             
> the
>   
>>>>>> switch contacts somehow generated an electronic "kick" (for want of a
>>>>>> better word) to start the oscillator, which then kept going of its
>>>>>>             
> own
>   
>>>>>> accord.  I wonder if what you are hearing is this "kick" starting the
>>>>>> oscillator for a few cycles, but then the line voltage is not
>>>>>>
>>>>>>             
>>> sufficient
>>>
>>>       
>>>>>> to keep the oscillator running.
>>>>>>
>>>>>> Martin
>>>>>>
>>>>>>
>>>>>>
>>>>>>             
>>>>> _______________________________________________
>>>>> VoIP mailing list
>>>>> VoIP at ckts.info
>>>>> http://lists.ckts.info/mailman/listinfo/voip
>>>>> Project Web Page: http://www.ckts.info/
>>>>>
>>>>>
>>>>>
>>>>>           
>>> _______________________________________________
>>> VoIP mailing list
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>>>
>>>
>>>       
>
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>   