Re: interface for modems with out of band signalling

[Alan <alan@lxorguk.ukuu.org.uk>]

> No, I am talking about how to support modems which don't have a
> command mode. These USB modems don't accept AT commands
> through the same channel as data. They take them encapsulated in special
> command messages to endpoint 0.
> How do I export this capability to user space? I am thinking about having
> two device nodes. But there may be a driver setting another precedent.
> Therefor I am asking.

ISDN4Linux provides a fake modem emulation in kernel space. The Nokia
phone drivers provide a user space manager which provides the interface.

So you've got precedents for both. If it's simply a case of splitting AT
commands off from the data and spotting guard bands and +++ you might
want to do it kernel side, if the second endpoint takes its own set of
phone control messages I guess its hairier.