LXR linux/Documentation/usb/acm.rst

   1======================
   2Linux ACM driver v0.16
   3======================
   4
   5Copyright (c) 1999 Vojtech Pavlik <vojtech@suse.cz>
   6
   7Sponsored by SuSE
   8
   90. Disclaimer
  10~~~~~~~~~~~~~
  11This program is free software; you can redistribute it and/or modify it
  12under the terms of the GNU General Public License as published by the Free
  13Software Foundation; either version 2 of the License, or (at your option)
  14any later version.
  15
  16This program is distributed in the hope that it will be useful, but
  17WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  18or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  19more details.
  20
  21You should have received a copy of the GNU General Public License along
  22with this program; if not, write to the Free Software Foundation, Inc., 59
  23Temple Place, Suite 330, Boston, MA 02111-1307 USA
  24
  25Should you need to contact me, the author, you can do so either by e-mail -
  26mail your message to <vojtech@suse.cz>, or by paper mail: Vojtech Pavlik,
  27Ucitelska 1576, Prague 8, 182 00 Czech Republic
  28
  29For your convenience, the GNU General Public License version 2 is included
  30in the package: See the file COPYING.
  31
  321. Usage
  33~~~~~~~~
  34The drivers/usb/class/cdc-acm.c drivers works with USB modems and USB ISDN terminal
  35adapters that conform to the Universal Serial Bus Communication Device Class
  36Abstract Control Model (USB CDC ACM) specification.
  37
  38Many modems do, here is a list of those I know of:
  39
  40        - 3Com OfficeConnect 56k
  41        - 3Com Voice FaxModem Pro
  42        - 3Com Sportster
  43        - MultiTech MultiModem 56k
  44        - Zoom 2986L FaxModem
  45        - Compaq 56k FaxModem
  46        - ELSA Microlink 56k
  47
  48I know of one ISDN TA that does work with the acm driver:
  49
  50        - 3Com USR ISDN Pro TA
  51
  52Some cell phones also connect via USB. I know the following phones work:
  53
  54        - SonyEricsson K800i
  55
  56Unfortunately many modems and most ISDN TAs use proprietary interfaces and
  57thus won't work with this drivers. Check for ACM compliance before buying.
  58
  59To use the modems you need these modules loaded::
  60
  61        usbcore.ko
  62        uhci-hcd.ko ohci-hcd.ko or ehci-hcd.ko
  63        cdc-acm.ko
  64
  65After that, the modem[s] should be accessible. You should be able to use
  66minicom, ppp and mgetty with them.
  67
  682. Verifying that it works
  69~~~~~~~~~~~~~~~~~~~~~~~~~~
  70
  71The first step would be to check /sys/kernel/debug/usb/devices, it should look
  72like this::
  73
  74  T:  Bus=01 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#=  1 Spd=12  MxCh= 2
  75  B:  Alloc=  0/900 us ( 0%), #Int=  0, #Iso=  0
  76  D:  Ver= 1.00 Cls=09(hub  ) Sub=00 Prot=00 MxPS= 8 #Cfgs=  1
  77  P:  Vendor=0000 ProdID=0000 Rev= 0.00
  78  S:  Product=USB UHCI Root Hub
  79  S:  SerialNumber=6800
  80  C:* #Ifs= 1 Cfg#= 1 Atr=40 MxPwr=  0mA
  81  I:  If#= 0 Alt= 0 #EPs= 1 Cls=09(hub  ) Sub=00 Prot=00 Driver=hub
  82  E:  Ad=81(I) Atr=03(Int.) MxPS=   8 Ivl=255ms
  83  T:  Bus=01 Lev=01 Prnt=01 Port=01 Cnt=01 Dev#=  2 Spd=12  MxCh= 0
  84  D:  Ver= 1.00 Cls=02(comm.) Sub=00 Prot=00 MxPS= 8 #Cfgs=  2
  85  P:  Vendor=04c1 ProdID=008f Rev= 2.07
  86  S:  Manufacturer=3Com Inc.
  87  S:  Product=3Com U.S. Robotics Pro ISDN TA
  88  S:  SerialNumber=UFT53A49BVT7
  89  C:  #Ifs= 1 Cfg#= 1 Atr=60 MxPwr=  0mA
  90  I:  If#= 0 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=ff Prot=ff Driver=acm
  91  E:  Ad=85(I) Atr=02(Bulk) MxPS=  64 Ivl=  0ms
  92  E:  Ad=04(O) Atr=02(Bulk) MxPS=  64 Ivl=  0ms
  93  E:  Ad=81(I) Atr=03(Int.) MxPS=  16 Ivl=128ms
  94  C:* #Ifs= 2 Cfg#= 2 Atr=60 MxPwr=  0mA
  95  I:  If#= 0 Alt= 0 #EPs= 1 Cls=02(comm.) Sub=02 Prot=01 Driver=acm
  96  E:  Ad=81(I) Atr=03(Int.) MxPS=  16 Ivl=128ms
  97  I:  If#= 1 Alt= 0 #EPs= 2 Cls=0a(data ) Sub=00 Prot=00 Driver=acm
  98  E:  Ad=85(I) Atr=02(Bulk) MxPS=  64 Ivl=  0ms
  99  E:  Ad=04(O) Atr=02(Bulk) MxPS=  64 Ivl=  0ms
 100
 101The presence of these three lines (and the Cls= 'comm' and 'data' classes)
 102is important, it means it's an ACM device. The Driver=acm means the acm
 103driver is used for the device. If you see only Cls=ff(vend.) then you're out
 104of luck, you have a device with vendor specific-interface::
 105
 106  D:  Ver= 1.00 Cls=02(comm.) Sub=00 Prot=00 MxPS= 8 #Cfgs=  2
 107  I:  If#= 0 Alt= 0 #EPs= 1 Cls=02(comm.) Sub=02 Prot=01 Driver=acm
 108  I:  If#= 1 Alt= 0 #EPs= 2 Cls=0a(data ) Sub=00 Prot=00 Driver=acm
 109
 110In the system log you should see::
 111
 112  usb.c: USB new device connect, assigned device number 2
 113  usb.c: kmalloc IF c7691fa0, numif 1
 114  usb.c: kmalloc IF c7b5f3e0, numif 2
 115  usb.c: skipped 4 class/vendor specific interface descriptors
 116  usb.c: new device strings: Mfr=1, Product=2, SerialNumber=3
 117  usb.c: USB device number 2 default language ID 0x409
 118  Manufacturer: 3Com Inc.
 119  Product: 3Com U.S. Robotics Pro ISDN TA
 120  SerialNumber: UFT53A49BVT7
 121  acm.c: probing config 1
 122  acm.c: probing config 2
 123  ttyACM0: USB ACM device
 124  acm.c: acm_control_msg: rq: 0x22 val: 0x0 len: 0x0 result: 0
 125  acm.c: acm_control_msg: rq: 0x20 val: 0x0 len: 0x7 result: 7
 126  usb.c: acm driver claimed interface c7b5f3e0
 127  usb.c: acm driver claimed interface c7b5f3f8
 128  usb.c: acm driver claimed interface c7691fa0
 129
 130If all this seems to be OK, fire up minicom and set it to talk to the ttyACM
 131device and try typing 'at'. If it responds with 'OK', then everything is
 132working.
 133