# Phoenix Sound USB Interface



## flysooner9 (Feb 16, 2016)

Was wondering if anyone knew of a substitute to the phoenix sound usb package? 90 bucks seems absurd for what seems like a usb cord and a 2.5mm adapter. Especially since the software can be downloaded.


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## Scottychaos (Jan 2, 2008)

I asked the same question a year ago:

http://forums.mylargescale.com/40-rc-battery-operations/71994-building-battery-sound-car-5.html

The answer is: you can *technically* make your own cord, in theory, but I doubt anyone has ever actually done it. Realistically, you really do have to pay the $80. I did, and now im glad I have the PC interface.

Scot


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## Paul Burch (Jan 2, 2008)

Contact me. $50.00 plus shipping and I will send you a plug and play set just as it comes from Phoenix. I ended up with a spare that came with some other things that I purchased.


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## Greg Elmassian (Jan 3, 2008)

Be happy you found a deal, the original cost for many sound programmer "dongles" is $200, I paid that for a Zimo, and for a C.T. Electronik.

Greg - 649


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## Paul Burch (Jan 2, 2008)

I will give "flysooner9" a couple more days to respond to my offer. After that its open to whoever wants it for $50.00 plus shipping. I have no idea who flysooner9 is. I like real names.


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## Dick413 (Jan 7, 2008)

Paul I will take it if fysooner9 does not.
Dick


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## Paul Burch (Jan 2, 2008)

Ok Dick. You are first in line. I will wait through the weekend. If no response from flysooner9 it is yours.


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## Paul Burch (Jan 2, 2008)

Dick,
It is yours if you still want it. I have sent you a pm.


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## Dick413 (Jan 7, 2008)

Yes Paul I still want it did not get a PM 
Thanks Dick


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## Treeman (Jan 6, 2008)

flysooner9 said:


> Was wondering if anyone knew of a substitute to the phoenix sound usb package? 90 bucks seems absurd for what seems like a usb cord and a 2.5mm adapter. Especially since the software can be downloaded.


I believe Phoenix will supply a schematic. I hear that is not worth the while to build one.


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## Scottychaos (Jan 2, 2008)

Treeman said:


> I believe Phoenix will supply a schematic. I hear that is not worth the while to build one.


yes, and yes.
I got the list of parts and the schematic from Phoenix. 17 individual parts needed, and a very complicated schematic I didnt even begin to understand. I didnt even attempt it.

Scot


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## Greg Elmassian (Jan 3, 2008)

I'd love to see the schematic, just out of curiosity. Funny, if it is simply a usb to serial converter, it's done with even fewer parts now.

Could you email me a copy Scot?

Greg


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## Paul Burch (Jan 2, 2008)

That's all I ever thought it was is a usb serial converter. In any case the spare I had is sold.


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## Scottychaos (Jan 2, 2008)

Greg Elmassian said:


> I'd love to see the schematic, just out of curiosity. Funny, if it is simply a usb to serial converter, it's done with even fewer parts now.
> 
> Could you email me a copy Scot?
> 
> Greg


Greg,
email sent..
Scot


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## Greg Elmassian (Jan 3, 2008)

Thanks Scot.

Well, it is NOT a USB to RS-232 converter... they did some funny stuff


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## ereuter (Feb 7, 2017)

Here is the schematic for anyone else who is interested. The basic rundown is this: 

The FT232RL is a USB-Serial converter. LMC7221 is a comparator. 

There are two data lines to the sound module, plus ground: DATA and PLUS_5.
When the board is connected, it sends a continuous 5 V back to the interface. This saturates Q1, pulling the CTS (clear to send) line on the FT232RL to ground, telling the computer software that the board is connected. 
The TXD pin on the FT232RL sends data directly to the DATA i/o pin.
When it's time to listen, TXD presumably goes into a high impedance mode, and RXD receives data from DATA. 
The comparator provides a voltage threshold that must be exceeded by the incoming data from the sound module to improve noise immunity.

(Edited a couple times for accuracy.)


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## ereuter (Feb 7, 2017)

I have been curious for a while what was actually going back and forth, but hadn't gotten around to checking. I threw a logic analyzer on it this morning, and have edited my previous post to correct an error.
The sound module always produces 5 V on the PLUS_5 line. This tells the computer that a board is connected.

The transfer of data is initialized by the computer sending a command followed by /r (carriage return). The board then responds with a packet of data. The packet contains 8 bytes, followed by "/r /n >"
It runs at 9600 baud. No wonder it takes so long to transfer a ROM file.


Here's a typical exchange:


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## Greg Elmassian (Jan 3, 2008)

actually eric, when q1 conducts, doesn't it pull CTS low? when not conducting, the 4.7 pullup is high, so CTS seems to be enabled low.

Q1 is biased by the 5 volt signal that should be there when the decoder is connected.

Greg


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## ereuter (Feb 7, 2017)

Of course. I hope none of my students saw this, since we literally covered BJTs on Wednesday. It's there to invert the logic since the steady state for RS-232 is high. I'll edit my description for posterity. 

The question that you and I both have, I think, is why they would waste a line on this and share the data line instead of having separate rx/tx lines. Must be some legacy reason.


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## ereuter (Feb 7, 2017)

I have an official interface, so it's not high on my list, but if someone wanted to tackle building their own, an easy way to knock off some of the parts on the schematic would be to just buy one of these: https://www.amazon.com/HiLetgo-FT232RL-Converter-Adapter-Breakout/dp/B00IJXZQ7C/ref=sr_1_1?ie=UTF8&qid=1511012750&sr=8-1


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## Greg Elmassian (Jan 3, 2008)

Well, I would say, since it was invented a long time ago, it was probably so they could sell the proprietary interface.

I've bought a number of proprietary interfaces for programming decoders over the years.

It's really silly to combine the tx and rx lines, but it could also have been that they wanted flow control, remember old RS-232 stuff did not have very fast interfaces and computers were slow, so they could not buffer the data without overrun... look at the history of the CTS/RTS/DSR/DTR lines in the old "modem" interfaces.

In any case, no off the shelf product would be available.

Greg


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