How to implement Read instead of WaitExten?

Question

Asterisk

Good day! Tell me how to make Read instead of WaitExten ??

[custom_conferenc]
exten => s,1,Answer()
exten => s,n,Background(/var/lib/asterisk/festivalcache/7b9f2e1)
exten => s,n,WaitExten(8)

exten => _XXX,1,AGI(private.php,${CALLERID(num)},${EXTEN})
exten => _XXX,n,Goto(${goto3})
exten => _XXX,n,AGI(say.php,${starttext})
exten => _XXX,n,Set(CONFBRIDGE(user,marked)=${marked})
exten => _XXX,n,Set(CONFBRIDGE(user,admin)=${marked})
exten => _XXX,n,Set(CONFBRIDGE(user,music_on_hold_when_empty)=no)
exten => _XXX,n,Set(CONFBRIDGE(user,end_marked)=yes)
exten => _XXX,n,ConfBridge(${EXTEN}_private,,${ссс_PROFILE2},${MENU_PROFILE2})   
exten => _XXX,n,Set(CONFBRIDGE(user,marked)=no)
exten => _XXX,n,Set(CONFBRIDGE(user,admin)=no)
exten => _XXX,n,Goto(custom_ivr,s,4)
exten => _XXX,n,AGI(say.php,"конференции не существует")
exten => _XXX,n,Goto(s,2)
exten => _XXX,n,AGI(say.php,"В конференции нет никого")
exten => _XXX,n,Goto(s,2)

exten => *,1,Goto(custom_ivr,s,8)
exten => t,1,Goto(s,1)
exten => i,1,Goto(s,1)

exten => h,1,Goto(s,1)

Answer 1

exten => s,n,Read(Code,,,,,8)
exten => GotoIf($[${DIALPLAN_EXISTS(custom_conferenc,${Code},1)}=1]?custom_conferenc,${Code},1:custom_conferenc,i,1)

Answer 2

Maximum 3 digits and wait no more than 8 seconds to enter
[custom_conferenc]
exten => s,1,Answer()
exten => s,n,Read(cifra,/var/lib/asterisk/festivalcache/7b9f2e1,,,3, 8)
exten => s,n,NoOp(entered the numbers ${cifra})
exten => s,n,ExecIf($[${LEN(${cifra})} = 3]?Goto(nabor))
exten = > s,n,Gotoif($["${cifra}" = "*" ]?Goto(custom_ivr,s,8))
exten => s,n,NoOp(tie out or entered incorrectly)
exten => s ,n,Goto(s,1)
exten => s,n(nabor),NoOp(Dial ${cifra})
exten => s,n,Set(EXTEN=${cifra})
exten => _XXX,1 ,AGI(private.php,${CALLERID(num)},${EXTEN})
exten => _XXX,n,Goto(${goto3})
exten => _XXX,n,AGI(say.php,${starttext })
exten => _XXX,n,Set(CONFBRIDGE(user,marked)=${marked})
exten => _XXX,n,Set(CONFBRIDGE(user,admin)=${marked})
...
and so on
Possible text errors to be checked