Modem Daughter Card (MDC)

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Modem Daughter Card (MDC)

This is a AC97 Modem Adapter that is installed in a CDC slot.


  • Chipset: Ambit (formerly Lucent Microelectronics)

IBM Partnumbers

IBM FRU PN: 91P7657, 26P8477, 26P8256

Also known (in IBM literature) as....

  • CDC Modem Card
  • V.90 Modem Daughter Card (MDC)
  • Modem Card, Ambit
  • Ambit Modem Daughter Card

Linux driver

The Linux driver from SmartLink supports this device.
Latest version of this driver is 2.9.11.

The ALSA AC'97 modem driver (snd_intel8x0m) should be used instead of the proprietary kernel module from SmartLink (see README ALSA mode), as it avoids tainting your kernel, and does not require a recompile each time you update your kernel version.

For Debian there is a sl-modem-daemon deb.


There is a slmodem rpm in the RPM-Fusion nonfree repository. Once you have installed the package, you need to edit /etc/sysconfig/slmodem and set INTERFACE=alsa and ALSA_DEVICE=modem:1

If ALSA_DEVICE=modem:1 does not work, run cat /proc/asound/cards and use the number before the Modem line

In addition you can set the country for the correct recognition of dialling and busy tones, and to adhere to any local (possibly legal) requirements. If you do not set the country, it will default to USA.

You can then start the service, and set it to autostart on boot

service slmodem start
chkconfig slmodem on

After this you should have a /dev/ttySL0 device

ThinkPads this card may be found in