These are the Dahdi references:
From the Asterisk Development Team
This is the up-to-date Dahdi reference site
This is the Dahdi tools up-to-date reference site
This is the official Dahdi Interface Driver Readme file
Voip-info.org has an excellent page on the Zaptel options (Dahdi is version 2 of Zaptel) which is a good reference for configurations.
This is website has more information on Dahdi then you care to know. It that may help in configuring and troubleshooting Dahdi and this section does Dahdi performance testing
[Linux Command Line Tools] - These are Linux command line tools. The Dahdi HW Module utilizes some of these tools behind the scenes to aid in configuring Dahdi devices:
[Asterisk CLI Tools] - These are the Asterisk CLI tools available to use for Dahdi. To enter the Asterisk CLI, type "asterisk -rvv" (two v's) from the Linux command prompt.
Wiki: Asterisk CLI Tools
Wiki: Linux Command Line Tools
Wiki: Webmin Dahdi HW module Wiki Home