Works OK at 5V TTL levels over short distance, but fails when through 1488/1489 RS232 level shifters at 38400 over a couple of metres.XorA wrote:..ooOOSilvester wrote: Indeed, but it is at least reliable. I always thought QL IPC serial was dodgy, but I've yet to get a USB serial adaptor to work on a laptop above 9600 reliably (CH340 or PL2303).![]()
I have about a billion of those things due to my job, never had a problem with them.
USB Keyboard Adapter for the QL
Re: USB Keyboard Adapter for the QL
David
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Re: USB Keyboard Adapter for the QL
Thats because you need rs-485 at those distances.Works OK at 5V TTL levels over short distance, but fails when through 1488/1489 RS232 level shifters at 38400 over a couple of metres.
Re: USB Keyboard Adapter for the QL
Using QXL or Q40 with 16650 UART RS232 levels at 38400 to MIDI works OK. Also using QPC1/2 emulators on PC with 16650 works.XorA wrote:Thats because you need rs-485 at those distances.Works OK at 5V TTL levels over short distance, but fails when through 1488/1489 RS232 level shifters at 38400 over a couple of metres.
Just cannot get a USB serial adaptor to work at those speeds, even just trying Minicom on Lubuntu fails.
I also have a Yamaha CBX-T3 which can convert 38400 to MIDI 31250. It has RS485 interface which will also works as RS232, though even trying a RS485 link failed.
I did notice the laptop PSU (switched mode) does cause a lot of noise on USB ground. But problem still occurs when running off battery.
Pity, I wrote a voice editor/filer for Yamaha SY35 using EasyPtr which would have been nice to use on laptop with emulator.
(The less said about the CH345 USB MIDI interface the better

David
Re: USB Keyboard Adapter for the QL
Solution was to use tiny MAX3232 powered from same USB port (attempts with external MC1488/1489 circuit failed):XorA wrote:..ooOOSilvester wrote: Indeed, but it is at least reliable. I always thought QL IPC serial was dodgy, but I've yet to get a USB serial adaptor to work on a laptop above 9600 reliably (CH340 or PL2303).![]()
I have about a billion of those things due to my job, never had a problem with them.
http://www.ebay.co.uk/itm/5PCS-Mini-RS2 ... SwdzVXiFJm
David
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Re: USB Keyboard Adapter for the QL
Is there a UK version of this board yet. Would be willing to test/help convert if needed.
Cheers,
Andy.
Cheers,
Andy.