It looks like people commonly use this kind of dialplan when receiving faxes on Asterisk, with a jump to extension fax during the Wait() if a fax tone is detected:
exten => _X.,1,Answer()
exten => _X.,n,Wait(n)
exten => _X.,n,…do stuff… exten => _X.,n,Hangup()
exten => fax,1,Goto(fax-rx,receive,1)
exten => receive,1,… exten => receive,n,…do stuff… exten => receive,n,ReceiveFAX()
This is well suited in case Asterisk needs to receive both voice and fax calls. But what if Asterisk is only used to receive fax calls, can we start directly at the fax-rx context? I’ve heard that it’s better to wait a few seconds before calling ReceiveFAX(), is it still necessary in case we don’t actually need fax detection?