Chapter 13. Managing Your Asterisk System

It won't be covered in the book. The source code has to be useful for something, after all.

—Larry Wall

While there is a cornucopia of creative things that you are going to want to do with your spanking-new Asterisk system, there are also some basic, non-glamourous, dare-we-say-boring things that need to be discussed.

13.1. Call Detail Recording

Without even being told, Asterisk assumes that you want to store CDR information^[149].

By default, Asterisk will create a CSV^[150] file and place it in the folder /var/log/asterisk/cdr-csv/. To the naked eye, this file looks like a bit of a mess. If, however, you separate each line according to the commas, you will find that each line contains information about a particular call, and that the commas separate the following values:

accountcode: Assigned if configured for the channel in the channel configuration file (i.e., sip.conf). The account code is assigned on a per-channel basis. You can also change this value from the dialplan by setting CDR(accountcode).
src: Received Caller*ID (string, 80 characters).
dst: Destination extension.
dcontext: Destination context.
clid: Caller*ID with text (80 characters).
channel: Channel used (80 characters).
dstchannel: Destination channel, if appropriate (80 characters).
lastapp: Last application, if appropriate (80 characters).
lastdata: Last application data (arguments, 80 characters).
start: Start of call (date/time).
answer: Answer of call (date/time).
end: End of call (date/time).
duration: Total time in system, in seconds (integer), from dial to hangup.
billsec: Total time call is up, in seconds (integer), from answer to hangup.
disposition: What happened to the call (ANSWERED, NO ANSWER, BUSY).
amaflags: What flags to use (DOCUMENTATION, BILL, IGNORE, etc.), specified on a per-channel basis, like accountcode. AMA flags stand for Automated Message Accounting flags, which are somewhat standard (supposedly) in the industry.
userfield: A user-defined field, maximum 255 characters.

^[149]If you are wondering why such an obviously simple thing seems to be such an achievement, the reason is simply that many traditional PBXs do not have this capability built in. With those systems, you have to purchase some sort of third party appliance even just to capture the raw call data. Asterisk simply stores it. No drama. No cost. No kidding.

^[150]A Comma Separated Values (CSV) file is a common method of formatting database-type information in a text file. You can open CSV files with a text editor, but most spreadsheet and database programs will also read them and properly parse them into rows and columns.