document a bit the use of templates.

They are highly convenient for writing configuration files, especially
if you have many similar entries, or want to switch quickly between
different configurations without having to comment/uncomment large
sections of the files.



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@44579 65c4cc65-6c06-0410-ace0-fbb531ad65f3

configs/sip.conf.sample

@@ -486,7 +486,51 @@ srvlookup=yes			; Enable DNS SRV lookups on outbound calls
 ; If Asterisk is on a public IP, and the phone is inside of a NAT device
 ; you will need to configure nat option for those phones.
 ; Also, turn on qualify=yes to keep the nat session open
+;
+; Because you might have a large number of similar sections, it is generally
+; convenient to use templates for the common parameters, and add them
+; the the various sections. Examples are below, and we can even leave
+; the templates uncommented as they will not harm:
 
+[basic-options](!)		; a template
+	dtmfmode=rfc2833
+	context=from-office
+	type=friend
+
+[natted-phone](!,basic-options)	; another template inheriting basic-options
+	nat=yes
+	canreinvite=no
+	host=dynamic
+
+[public-phone](!,basic-options)	; another template inheriting basic-options
+	nat=no
+	canreinvite=yes
+
+[my-codecs](!)		; a template for my preferred codecs
+	disallow=all
+	allow=ilbc
+	allow=g729
+	allow=gsm
+	allow=g723
+	allow=ulaw
+
+[ulaw-phone](!)		; and another one for ulaw-only
+	disallow=all
+	allow=ulaw
+
+; and finally instantiate a few phones
+;
+; [2133](natted-phone,my-codecs)
+;	secret = peekaboo
+; [2134](natted-phone,ulaw-hone)
+;	secret = not_very_secret
+; [2136](public-phone,ulaw-hone)
+;	secret = not_very_secret_either
+; ...
+;
+
+; Standard configurations not using templates look like this:
+;
 ;[grandstream1]
 ;type=friend 			
 ;context=from-sip		; Where to start in the dialplan when this phone calls