path: root/README

Zapata Telephony Interface Driver
=================================
Asterisk Development Team <asteriskteam@digium.com>
$Revision$, $Date$

Zaptel is a short for ZAPata TELephony.

Supported Hardware
------------------
Digital Cards
~~~~~~~~~~~~~
- wct4xxp: 
  - Digium newer quad-span T1/E1/J1 cards: Wildcard TE420P/TE410P/TE405P 
  - Digium newer dual-span T1/E1/J1 cards: Wildcard TE220P/TE210P/TE205P 
- wcte12xp: Digium Wildcard TE120P and the TE122P single-span T1/E1/J1 card
- wcte11xp: Digium Wildcard TE110P T1/E1/J1
- wct1xxp: 
  - Wildcard T100P (old single-span T1)
  - Wildcard E100P (old single-span E1)
- tor2: Tormenta quad-span T1/E1 card from the Zapata Telephony project
- torisa: The old dual-span ISA T1 card from Zapata Telephony


Analog Cards
~~~~~~~~~~~~
- wctdm24xxp: 
  - Digium TDM2400P card: up to 24 analog ports
  - Digium TDM800P card: up to 8 analog ports
- wctdm: Digium TDM400P card: up to 4 analog ports
- xpp: Xorcom Astribank: a USB connected unit of up to 32 ports
  (also BRI)
- wcfxo: X100P, similar and clones. A simple single-port FXO card
- wcusb: Digium S100U: A simple single-port USB FXS unit


Other Drivers
~~~~~~~~~~~~~
- pciradio: Zapata Telephony PCI Quad Radio Interface
- wctc4xxp: Digium hardware transcoder cards (also need zttranscode)
- ztd-eth: TDM over Ethernet (TDMoE) driver. Requires ztdynamic
- ztd-loc: Mirror a local span. Requires ztdynamic
- ztdummy: A dummy driver that only provides a zaptel timing source.


Build Requirements
------------------
You will need a matching kernel source tree and a working Linux build 
system. Some of the programs require some additional libraries.


Kernel Source / "Headers"
~~~~~~~~~~~~~~~~~~~~~~~~~
- Building zaptel requires a kernel build tree.
- This should basically be at least a partial kernel source tree and
  most importantly, the exact kernel .config file used for the build as
  well as several files generated at kernel build time.
- KERNEL_VERSION is the output of the command `uname -r`
- If you build your own kernel, you need to point to the exact kernel
  build tree. Luckily for you, this will typically be pointed by the
  symbolic link /lib/modules/KERNEL_VERSION/build which is the location
  zaptel checks by default.
- If you use a kernel from your distribution you will typically have a
  package with all the files required to build a kernel modules for your
  kernel image.
  * On Debian Etch and above and any Ubuntu this is
    +++ linux-headers-`uname -r` +++
  * On Fedora RHEL and compatibles (e.g. CentOS) this is the
    kernel-devel package. Or if you run kernel-smp or kernel-xen, you
    need kernel-smp-devel or kernel-xen-devel, respectively.
  * On SUSE you seem to need the package kernel-source .
  * In some distributions (e.g.: in RHEL/CentOS, Fedora, Ubuntu) the 
    installation of the kernel-devel / kernel-headers package will 
    be of a version that is newer than the one you currently run. In 
    such a case you may need to upgrade the kernel package itself as 
    well and reboot.
- To point explicitly to a different build tree: set KSRC to the kernel 
  source tree and KVERS to the exact kernel version:

  make KVERS=2.6.18.Custom KSRC=/home/tzafrir/kernels/2.6.18


Kernel Configuration
~~~~~~~~~~~~~~~~~~~~
If you build a custom kernel, note the following configuration items:

- CONFIG_CRC_CCITT must be enabled ('y' or 'm'). On 2.6 kernels this can 
  be selected These can be selected from the "Library Routines" submenu 
  during kernel configuration via "make menuconfig".
- If you don't have any zaptel hardware, you need ztdummy.
  * ztdummy on i386/amd64 and later kernels (>= 2.6.15) can (and should)
    use the system's RTC (Real Time Clock).
  * Alternatives to that for ztdummy are a UHCI USB controller (USB
    controllers made by Intel or VIA) or a kernel that has HZ=1000
    (default on kernels 2.6.0-2.6.12, optional on newer kernels. Not
    possible on 2.4).


A Build System
~~~~~~~~~~~~~~
gcc and friends. Generally you will need to install the package gcc.
There may be cases where you will need a specific version of gcc to build
kernel modules.


Extra Libraries
~~~~~~~~~~~~~~~
Some libraries are needed for extra utilities that are provided with
Zaptel

- libusb is needed for building fpga_load, needed for firmware loading of
  the Xorcom Astribank.
- libnewt is needed to build the optional but useful utility zttool.


Distribution-Specific Instructions
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
==== Debian 4.0 (Etch)
  apt-get install linux-headers-`uname -r` build-essential libnewt-dev libusb-dev

==== Debian 3.1 (Sarge)
  apt-get install kernel-headers-`uname -r` build-essential libnewt-dev libusb-dev

==== RHEL4 / CentOS 4
You need the following non-kernel-related packages:

  yum install gcc newt-devel libusb-devel

If the following command produces an error, you need to install
ithe kernel devel package:

  ls /lib/modules/`uname -r`/build/.config

The right one depends on your kernel version. If the following command
produces output you have an SMP kernel:

  uname -r | grep smp

and thus need to run:

  yum install kernel-smp kernel-smp-devel

If that command produced no output, you have a non-SMP kernel:

  yum install kernel kernel-devel

At this point you should probably reboot to get the new kernel in effect.


Installation
------------
----------------------------------
./configure
# optional step: select custom configuration:
#make menuconfig
make
make install
# To install init scripts and config files:
#make config

Note: If using `sudo` to build/install, you may need to add /sbin to your PATH.
----------------------------------


Zaptel PERL modules
-------------------
The directory xpp/utils has, in addition to helper utilities for the
Xorcom Astribank, a collection of perl modules to provide information
related to Zaptel. The perl modules themselves are under xpp/utils/zconf .
In xpp/utils there are several utilities that use those modules:
- xpp-specific: zt_registration, xpp_sync, xpp_blink .
- General: lszaptel, zapconf, zaptel_hardware

The zaptel perl modules will currently only be automatically installed
if you happen to isntall the xpp module. This should be the defualt, but
you can also initiate it manually by running:

  make -C xpp/utils install

Those utilities require the perl modules to be installed, however they
will also look for them in the directory zconf, and thus can be run
directly from the zaptel source tree. For example:

  ./xpp/utils/zaptel_hardware

To get usage information on a program, you can also use perldoc
(sometimes provided in a package separate from perl itself). For
instance:

  perldoc ./xpp/utils/xpp_blink

zapconf is currently experimental and intended to eventually replace
genzaptelconf by a more maintainable code.


Zaptel Device Files
-------------------
Userspace programs will usually interact with Zaptel through device
files under the /dev/zap directory (pedantically: characted device files 
with major number 196) . Those device files can be generated statically
or dynamically through the udev system.

* /dev/zap/ctl (196:0) - a general device file for various information and
  control operations on the zaptel channels.
* /dev/zap/NNN (196:NNN) - for NNN in the range 1-249. A device file for
  zaptel channel NNN. It can be used to read data from the channel
  and write data to the channel.
* /dev/zap/transcode (196:250) - Used to connect to a zaptel transcoding
  device.
* /dev/zap/timer (196:253) - Allows setting timers. Used anywhere?
* /dev/zap/channel (196:254) - Can be used to open an arbitrary zaptel
  channel. This is an alternative to /dev/zap/NNN that is not limited to
  249 channels.
* /dev/zap/pseudo (196:255) - A timing-only device. Every time you open
  it, a new Zaptel channel is created. That Zaptel channel is "pseudo" -
  Zaptel recieves no data in it, and only sends garbage data with the
  same timing as the Zaptel timing master device.


Zaptel Timing
-------------
A PBX system should generally have a single clock. If you are connected
to a telephony provider via a digital interface (e.g: E1, T1) you should
also typically use the provider's clock (as you get through the
interface). Hence one important job of Asterisk is to provide timing to
the PBX. 

Zaptel "ticks" once per millisecond (1000 times per second). On each
tick every active zaptel channel reads and 8 bytes of data. Asterisk
also uses this for timing, through a zaptel pseudo channel it opens.

However, not all PBX systems are connected to a telephony provider via
a T1 or similar connection. With an analog connection you are not synced
to the other party. And some systems don't have Zaptel hardware at all.
Even a digital card may be used for other uses or is simply not
connected to a provider. Zaptel cards are also capable of providing timing 
from a clock on card. Cheap x100P clone cards are sometimes used for
that pupose.

If all the above fail, you can use the module ztdummy to provide timing
alone without needing any zaptel hardware. It will work with most
systems and kernels.

You can check the zaptel timing source with zttest, which is a small 
utility that is included with zaptel. It runs in cycles. In each such
cycle it tries to read 8192 bytes, and sees how long it takes. If zaptel
is not loaded or you don't have the device files, it will fail
immedietly. If you lack a timing device it will hang forever in the
first cycle. Eitherwise it will just give you in each cycle the percent
of how close it was. Also try running it with the option -v for a
verbose output.


Spans and Channels
------------------
Zaptel provides telephony *channels* to the userspace applications. 
Those channels are channels are incoreperated into logical units called
*spans*.

With digital telephony adapters (e.g: E1 or T1), a span normally 
represents a single port. With analog telephony a span typically
represents a PCI adapter or a similar logical unit.

Both channels and spans are identified by enumerating numbers (beginning
with 1). The number of the channel is the lowest unused one when it is
generated, and ditto for spans.


PROCFS Interface: /proc/zap
~~~~~~~~~~~~~~~~~~~~~~~~~~~
A simple way to get the current list of spans and channels each span
contains is the files under /proc/zaptel . /proc/zaptel is generated by
zaptel as it loads. As each span registers to Zaptel, a file under
/proc/zaptel is created for it. The name of that file is the number of
that span.

Each file has a 1-line title for the span followed by an empty line and
then a line for each channel of the span. 

The title line shows the number of the span, its name and title, and 
(potentially) the alarms in which it is.

The channel line for each channel shows its channel number, name and the
actual signalling assigned to it through ztcfg.


What is the license for the zaptel driver?
------------------------------------------
libpri is distributed under the terms of the GNU General Public License, 
which permit its use and linking with other GPL'd software only.  
The GNU GPL is included in the file LICENSE in this directory.

If you wish to use the zaptel drivers in an application for which the 
GPL is not appropriate (e.g. a proprietary embedded system), licenses
under more flexible terms can be readily obtained through Digium, Inc. 
at reasonable cost.


How do I report bugs or contribute?
-----------------------------------
Please report bug and patches to the Asterisk.org bug tracker at
http://bugs.digium.com in the "zaptel" category.


Does anything use this library so far?
--------------------------------------
Yes, the Asterisk Open Source PBX does. http://www.asterisk.org


Links
-----
- http://asterisk.org/ - The Asterisk PBX
- http://voip-info.org/
- http://voip-info.org/wiki/view/Asterisk+Zaptel+Installation
- http://www.zapatatelephony.org/ - A historical site.