Battery to USB for DSL Modem

Hi,

For remote testing purposes I've connected a USB modem to a 6V battery with a Rectifier Diode to drop the voltage to USB spec.

I want to test for a DSL connection on circuits without the link to a PC.

But when connected to the battery the modem does not initiate the DSL handshake sequence, so my question is:

Does the modem need a signal from the PC via the D +/- to start the DSL sequence. Would connecting the D +/- to the 5V or Earth provide the missing link?

Any Ideas?

Thanks!

I would imagine you need the computer to do all that? - if it's a USB modem then it's fairly dumb, it requires the computer to control it.

Something like that is likley nothing more than a hardware interface to the DSL line itself, the rest is probably done by the driver on the PC like Nigel was saying. Are you testing this battery hotwire on a line you can ordinarily get a DSL connection from when it's connected to a computer? Try it on a known working phone line that you can get a DSL connection from when it's connected to a PC, then try it with the battery. If it doesn't work then you need a USB host to control it.