1964 Antique MODEM Live Demo

[John Foust]

At 03:24 PM 6/1/2009, Gordon JC Pearce wrote:
>Okay, let's try again.  I have a circa-70s 300-baud modem, that will
>generate incorrect tones when it's plugged into a USB-to-serial
>converter, but not when it's plugged into a real serial port.
>Why might this happen?

USB only guarantees to supply 100 milliamps.  Up to 500 mA can be
negotiated with the controller, depending.  Might your older device
depend on more amps than the USB adapter can supply?

- John