Synopsis

Read a variable in the form for DTMF tones as pressed by the caller

Description

As of Asterisk 1.0:
 Read(variable[|filename][|maxdigits][|option])
As of Asterisk 1.2:
 Read(variable[|filename][|maxdigits][|option][|attempts][|timeout])
As of Asterisk 1.4:
 Read(variable[,filename][,maxdigits][,option][,attempts][,timeout])

Reads a #-terminated string of digits a certain number of times from the user in to the given variable.

• variable: variable where the user's response will be stored.
• filename: file to play before reading digits.
• maxdigits: maximum acceptable number of digits. Stops reading after maxdigits have been entered (without requiring the user press the '#' key). Defaults to 0 - no limit - wait for the user press the '#' key. Any value below 0 means the same. Max accepted value is 255.
• option: may be 'skip' to return immediately if the line is not up, or 'noanswer' to read digits even if the line is not up.
• attempts: if greater than 1, that many attempts will be made in the event no data is entered.
• timeout: Timeout in seconds. If greater than 0, that value will override the default timeout.

Read should disconnect if the function fails or errors out.

Example

; The Following Example uses Read and Say digits to read 3 digits from user, saying each one as user types.

Asterisk 1.2:
 exten => s,1,Gotoif($[ "${LEN(${extensao})}" < "3"]?3:100)
 exten => s,n,NoOp(Executing - ${extensao} - )
 exten => s,n,Read(digito||1)
 exten => s,n,SayDigits(${digito})
 exten => s,n,Set(extensao=${extensao}${digito})
 exten => s,n,GoTo(s,1)
 exten => s,100,GoTo(from-pstn,s,1)
 exten => h,1,hangup()

Asterisk 1.4, 1.6:
 exten => s,1(start),Gotoif($[ "${LEN(${extensao})}" < "3"]?collect:pstn)
 exten => s,n,NoOp(Executing - ${extensao} - )
 exten => s,n(collect),Read(digito,,1)
 exten => s,n,SayDigits(${digito})
 exten => s,n,Set(extensao=${extensao}${digito})
 exten => s,n,GoTo(start)
 exten => s,n(pstn),GoTo(from-pstn,s,1)
 exten => h,1,hangup()


; The following example is a work-around that mostly works at catching # as part of the dial string.
 ;Written in 1.8.  Compatibility unknown.
 exten => s,1,Set(wait=2)
 exten => s,n(begin),Playback("please-dial-now")
 exten => s,n,Set(gottries=0)
 exten => s,n,Set(got=)
 exten => s,n(getmore),Set(timer=${EPOCH})
 exten => s,n,Read(get,"silence/1",,,,${wait})
 exten => s,n,Set(timer=$${EPOCH}-${timer})
 exten => s,n,GotoIf($[${timer}==$${wait}+1]?gotnothing:gotsomething)
 
 ;I double-check the length of get below in case the user happened to enter
 ;digits, but did so in such a manner that the epoch math thinks nothing
 ;was entered.  I suppose the same could happen with pound, but because
 ;pressing pound ends the read (and thus shortens the epoch), It is much
 ;less likely.
 exten => s,n(gotnothing),Set(gottries=$${gottries}+1
 exten => s,n,GotoIf($${LEN(${get})} == 0?reallynothing:gotdigit)
 exten => s,n(reallynothing),GotoIf($${gottries}>1?done:getmore)
 
 exten => s,n(gotsomething),Set(gottries=0)
 exten => s,n,GotoIf($${LEN(${get})} == 0?gotpound:gotdigit)
 exten => s,n(gotpound),Set(got=${got}#)
 exten => s,n,Goto(getmore)
 exten => s,n(gotdigit),Set(got=${got}${get})
 exten => s,n,Set(get=)
 exten => s,n,Goto(getmore)
 
 exten => s,n(done),SayDigits(${got})
 exten => s,n,Goto(begin)
 
 ; Doubt we get here:
 exten => i,1,Playback("vm-goodbye")
 exten => i,n,Hangup()
 
 ; here either:
 exten => u,1,Playback("vm-goodbye")
 exten => u,n,Hangup()

Notes

Pipe characters ( | ) have been changed to commas in Asterisk 1.6.
In Asterisk 1.4, either pipes OR commas will work. Using commas will ease future upgrades.

'#' is the End-Of-Input Key. It is NOT possible to accept '#' with Read()

Warning:
In Asterisk 1.4: the "filename" field does not accept concatenation (file1&file2&file...). It does work in 1.8.4 and possibly earlier versions.

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