Remove all special characters from the dialed number

Some softphones / CTI solutions transmit a phone number with special characters when dialing, for example +371(2) 229-3042

Such a call is very likely to fail, it will be completed by mistake.

1. To solve the problem of "filtering" characters, an additional context should be described through the Customization of system files menu

1. We will edit the extensions.conf file.

1. Add the following context to the end of the file:

[all_peers-custom]

exten => s,1,NoOp(Cleaning dst number)
	same => n,Set(cleanNumber=${FILTER(\*\#1234567890,${EXTEN})})
	same => n,ExecIf($["${EXTEN}" != "${cleanNumber}"]?Goto(all_peers,${cleanNumber},1))
	same => n,return