Connecting hardware synthesizer to speakup without serial port.

Mike Ray mike at
Sun Apr 19 13:05:22 EDT 2015

It has nothing to do with when or whether the computer loads the driver
for the USB to serial adaptor.  It just doesn't support the
hardware-handshaking that speakup and the hardware synth need.

You might hear the effect that for the first few seconds it seems to
work but then goes silent.  I assume this is because speakup is waiting
for the hand-shake from the synth that indicates it has finished the
last chunk and is ready for more.

I had email once before about this privately from someone trying to use
a USB to serial adaptor and I recommended he install an RS232 serial
port card and that fixed his issues.


On 19/04/2015 17:10, Glenn / Lenny wrote:
> I have only used a USB to serial in Windows.
> But I thought that others had done it after the computer had gone through 
> its initial screens.
> Glenn
> ----- Original Message ----- 
> From: "Mike Ray" <mike at>
> To: <speakup at>
> Sent: Sunday, April 19, 2015 11:05 AM
> Subject: Re: Connecting hardware synthesizer to speakup without serial port.
> No, speakup and the Apollo, or any other hardware speech-synthesiser
> will not work with a USB to serial adaptor.
> I believe this to be because a genuine serial port (RS232) and speakup
> use the hardware hand-shaking pins (RTS and CTS?), to communicate
> readiness to send and recieve data.  The USB to serial adaptors will
> either not support this hardware hand-shaking or it takes a differently
> written program to use it.
> Mike
> On 19/04/2015 16:43, Glenn / Lenny wrote:
>> Hi,
>> I thought that it will work with a USB to serial adapter, but you may not
>> get the initial computer boot-up messages because the USB to serial driver
>> would not have been loaded yet.
>> Glenn
>> ----- Original Message ----- 
>> From: "Ĺ‚ukasz golonka" <wulfryk1 at>
>> To: <speakup at>
>> Sent: Sunday, April 19, 2015 6:01 AM
>> Subject: Connecting hardware synthesizer to speakup without serial port.
>> Hi. I have apollo II synthetiser. I would like  to connect it to
>> speakup, but i have computers without physical serial port. Usb to
>> serial interfaces don't work with speakup of course. Is it possible to
>> connect speakup to apollo. I've heard about possibility to connect
>> external synthetiser to speakup using express card to com adapter, but
>> my computer doesn't  have  physical express card port, so i must again
>> use express card to usb converter.
>> Thank you for help.
>> Lukasz.
>> _______________________________________________
>> Speakup mailing list
>> Speakup at
>> _______________________________________________
>> Speakup mailing list
>> Speakup at

Michael A. Ray
Witley, Surrey, South-east UK

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