This function allows you to cut a certain number of characters from the value of a variable.

Below, we will give you an example.

To use this application you need a working Asterisk PBX with registered users in iax.conf, sip.conf or mgcp.conf(It depends on which protocol you would like to use) and made extensions. We are using Asterisk version1.2.1.

To see how the application works we recommend you to use our IAX softphone Idefisk. You could download it from here. Please also read our tutorial to learn how to configure it to work with Asterisk PBX.

We need to create one user in the iax.conf file. This is because we are going to use the IAX2 protocol. If you want to use other protocol, such as SIP or MGCP, you have to do the configurations below respectively in sip.conf or mgcp.conf.

So, we have registered the user user1

Type=friend means that this user can make and receive calls. Host=dynamic means that the IP is not static but dynamic through a DHCP server. Allow=all means that the line which this user will use, could support all audio codecs. Context=test - this shows that this user is working with the extensions in this context of the configuration file extensions.conf.

Now lets take a look at the extensions.conf file.

On the picture above you could see our extensions.conf file.

In this example, when somebody dials 100, the call will be answered by the Answer application. The next executed extension will be the one which contains the ChanIsAvail application. As arguments in its brackets we have set IAX2/10.3.3.43. This will check whether this channel is available or not. If the channel is available then it will be set in the ${CHANISAVAIL} variable. We have one extension with the NoOp application, which we will use to check the content of the AVAILCHAN variable.


Because we are going to use only the first four signs before the first "/" character, we have to Cut the unnecessary part.

We want only the IAX2 abbreviation and we will use the CUT function to take only these characters.

We have to use the Set application. As argument in the brackets write the following - NEWVAR=${CUT(AVAILCHAN|/|1)}. So, this actually will cause the cut of the all characters before the first slash character and then these characters will be stored in the NEWVAR variable.

In the brackets of the CUT function we have AVAILCHAN|/|1. AVAILCHAN is the variable from which we would like to cut something. The next argument is the delimiter. By default it is set to "-". In our case we will change it to the /character. The last argument is the fieldspec one. We have set this parameter to 1, which means that the application will Cut all characters before the first "/" character. In other words, the application will start from the first sign and it will cut all the following characters until it reaches the first "/" character. The cut characters will be saved in the variable NewVar. In our case these characters are IAX2.

NOTE: Please, pay attention, that the both variables NEWVAR and AVAILCHAN are without the "${}" characters.

We use another NoOp application to check whether the result is the desired one. In our case this application returns IAX2, which is exactly what we have wanted.

So, lets use this variable for something. Lets call an user through the available channel. For that purpose we will use the Dial application. As argument in its brackets we will set the following: ${NewVar}/user1. Actually, ${NewVar} contains the IAX2 string, so the user user1 will be called through the channel IAX2.

Please pay attention that here, the variable NewVar is used with the ${} characters.

NOTE: The function CUT is case sensitive. You always have to write it in your dialplans with capital letters.

In order to be sure that the Asterisk PBX will hang up the line, when the conversation is over, it is a good idea to use the Hangup application.