From: Giovanni Maruzzelli <gmaruzz@gm...> - 2005-10-21 15:55:55
I would like to ask you libusb developers some counseils
I wrote a program to control cellphones through serial port and
soundcard (serial port to command the data port for AT commands like
dial, hangup, answer, etc; soundcard with alsa/oss to interact with
audio through the hadsfree jack).
This program works well, but is not scalable because you can't have
many cheap soundcard, serialports, etc in a computer (you would have
to buy multiserials, esoteric soundcards with multichannels
capabilities, etc). Also, alsa and oss does not supports more than 8
audio devices without breaking compatibilities (but they can be
I would like to hack a driver that allows me to use as many cheap usb
audio devices, and how many serial devices I want.
I just want to read and write audio (16bit 8khz /sec) from each usb
device, full duplex.
Also, I would like the same device to act as a serial port between
computer and cellphone (as the normal USB datacable - usbtoserial).
I need the same USB device to have the audio AND the serial
capabilities because I can't think to a way to correctly match the
audio and the command devices (I would end up sending commands to the
wrong cellphone, after a couple of plug in plug out).
I'm planning to use cheap USB sound adapters chip (Codecs, the kind
that drives handsets) and data cables chip (usbtoserials, the kind you
use to transfer logos in the cellphone, or to sync your phonebook).
I would like to end up with an expandable box where I can plug 64 -
256 cellphones, and USB seems the correct answer to bandwith,
pluggability and expandability (just daisy chaining hubs)
Do you see some obvious flaw in what I'm thinking about?
Do you think this can be done with usblib or I have to code a full
fledged kernel driver?
If I use USB2 hubs and USB1.1 codecs (or serials) the total bandwith
available to all the serial and codecs devices will be 480M/s or 32M/s
(I mean, each one would stay 1.1, but all in all?) ?
There is a way to make one only device out from a usbtoserial and an
audiocodec? Or a way to uniquely identify each of them so I can match
them in software (I mean, something else than firmware ;-) ) ?
Any hardware you can counseil?
And I would grateful take any further hints you wants to share.
Thanks a lot,