How To use mISDN hfc_multi module as external clock source for zaptel ztdummy

System:
	Asterisk with ISDN cards and analogous FAX in the same system.

Issue:
	Because of asynchronous clocks for the ISDN and FAX part, 
	transmission errors when faxing are common.

Solution:
	Use the same clock for ISDN and FAX.

	We provide patches to use several ISDN cards with HFC chips as a
	clock source for the zaptel ztdummy module.



Step 1: Download needed packages

	Download file zaptel-1.2.12.tar.gz from 
	http://ftp.digium.com/pub/zaptel/

	Unpack archive: 
		tar xzf zaptel-1.2.12.tar.gz

	Get mISDN via CVS:
        * Anonymous access using the pserver method with any cvs client
          Use the following commands:

       	  cvs -d :pserver:guest@cvs.isdn4linux.de:/i4ldev login
	  cvs -d :pserver:guest@cvs.isdn4linux.de:/i4ldev co mISDN

	  When asked for a password during login, enter "readonly" (without the quotes).

	Get patch from beroNet: ztdummy.patch.
	http://www.beronet.com/download


Step 2: Apply patch

	In directory zaptel-1.2.12:
		patch ztdummy.c path/to/ztdummy.patch


Step 3: Compile and install

	In directory zaptel-1.2.12 execute (as root):
		make install
	
	In directory mISDN-x_x_x execute (as root):
		make install


Step 4: Change configuration

	Edit mISDN configuration file /etc/misdn-init.conf, and
	add at the bottom of the file a line:

		timer=1


Step 5: Load modules

	First load ztdummy module (as root):
		modprobe ztdummy
	
	Then start mISDN (as root, too):
		misdn-init start
	
	ztdummy MUST be loaded beforce mISDN! 
	Dont try to unload ztdummy before you stopped mISDN!

Step 6: Start asterisk and be happy!