[VoIP] Temporary old busy and reorder tones up on 366

[Doug Alderdice]

At 05:41 PM 3/25/2007 -0400, Jayson Smith wrote:
>Hi all,
>I just called into Doug's switch. I don't know if it's volume level, or the
>characteristics of the Step or what, but the tones sound a bit different
>from what I sent. Also, there's a 120-cycle hum, especially on Reorder tone.
>Doug, I'm not putting down your efforts, I just wanted you to know what IMHO
>they sound like. For Doug and anybody else, a sample is at
>http://www.bluegrasspals.com/doug.wav
>Here, the first few seconds are a sample of the tone that I sent him. I
>actually sent him two different frequencies, and this is the one he chose to
>use. After that, we dial Busy, then we dial Reorder. Enjoy!

I am not surprised that the tones may sound a bit different.  The sample 
file that was sent to me was played through the sound card of my computer, 
connected to the analog input of the ISD chip.  The sample rate of the chip 
is hardly CD quality, it's only 6.4 kHz.  There's going to be a bit of a 
difference to discerning ears right there.  I didn't check any levels, I 
just hooked it up and recorded it, so I suspect that the recording may be a 
bit "hot" in the chip and a bit distorted.  I know the recording of 420/40 
that I put into a second chip for ringback definitely has that problem and 
needs to be re-recorded in the chip.

Wired into the switch, the output from the recorder chip is coupled through 
transformers to the dial tone and reorder circuits, which will introduce 
some more change in characteristics.

I haven't heard 120-Hz hum in my tests, but I haven't been in a quiet 
setting, either.  The fans in my computer are really loud so calling from 
the phones by the computer are not in a quiet environment, and working next 
to the switch in the basement I have loud 60-cycle hum from the power 
supply on the switch, as well as from my key systems, and then there's the 
fluorescent light fixtures in the cellar. I'll have to listen to your 
recording with headphones.  Seems like you mentioned some hum in your calls 
to Lee's switch, could it be something in your setup that's introducing the 
hum?

Thanks for the comments.  I know this isn't going to result in an 
absolutely perfect simulation of a real rotary tone generator, but I can 
try to tweak things that aren't quite right.  I'm interested in what others 
have to say as well, either publicly on the list or privately.

Doug.