dahdi-source software package provides DAHDI telephony interface - source code for kernel driver, you can install in your Debian 7 (Wheezy) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install dahdi-source
dahdi-source is installed in your system.
Make ensure the dahdi-source package were installed using the commands given below,
$ sudo dpkg-query -l | grep dahdi-source *
You will get with dahdi-source package name, version, architecture and description in a table
| Distro | Debian 7 wheezy |
| Section | Kernels |
| Package | dahdi-source |
| Version | 1:2.6.1+dfsg2-1 |
| Description | DAHDI telephony interface - source code for kernel driver |
| Sub Section | Kernels |