diff --git a/configs/mgcp.conf.sample b/configs/mgcp.conf.sample
index 3508a1b25460583f1b0cb5b98498acf0a85ca8d5..2279977d8e5a4fd8c9058db86cda947a58bedc1c 100644
--- a/configs/mgcp.conf.sample
+++ b/configs/mgcp.conf.sample
@@ -27,8 +27,8 @@
 ;context=local 
 ;host=192.168.1.20 
 ;callerid = "John Doe" <123> 
-;callgroup=0 
-;pickupgroup=0
+;callgroup=0      ; in the range from 0 to 63
+;pickupgroup=0    ; in the range from 0 to 63
 ;nat=no 
 ;threewaycalling=yes 
 ;transfer=yes     ; transfer requires threewaycalling=yes. Use FLASH to transfer
diff --git a/configs/misdn.conf.sample b/configs/misdn.conf.sample
index b4751fc19ba9c0a3080b19fe9807c1769cc781a3..6dd59c8052746916f5c7a882cfe8903137670fb3 100644
--- a/configs/misdn.conf.sample
+++ b/configs/misdn.conf.sample
@@ -233,6 +233,7 @@ incoming_early_audio=no
 ; Pickup and Callgroup
 ;
 ; deafult values: not set = 0
+; range: 0-63
 ;
 ;callgroup=1
 ;pickupgroup=1
diff --git a/configs/sip.conf.sample b/configs/sip.conf.sample
index d391ec7c68bace86f2a6fff8dc3bb804c174bb78..26966cd089b644965e0c8ab88a68f226e2153ce8 100644
--- a/configs/sip.conf.sample
+++ b/configs/sip.conf.sample
@@ -473,6 +473,9 @@ srvlookup=yes			; Enable DNS SRV lookups on outbound calls
 ;qualify=1000			; Consider it down if it's 1 second to reply
 				; Helps with NAT session
 				; qualify=yes uses default value
+;
+; Call group and Pickup group should be in the range from 0 to 63
+;
 ;callgroup=1,3-4		; We are in caller groups 1,3,4
 ;pickupgroup=1,3-5		; We can do call pick-p for call group 1,3,4,5
 ;defaultip=192.168.0.60		; IP address to use if peer has not registred
diff --git a/configs/zapata.conf.sample b/configs/zapata.conf.sample
index 0ab51441fe2f8c1650f922d82bc5f348bcdd099f..95bfb9a6ef418bba6ead3173df4dcc2aea0f5040 100644
--- a/configs/zapata.conf.sample
+++ b/configs/zapata.conf.sample
@@ -354,7 +354,7 @@ group=1
 ; Ring groups (a.k.a. call groups) and pickup groups.  If a phone is ringing
 ; and it is a member of a group which is one of your pickup groups, then
 ; you can answer it by picking up and dialing *8#.  For simple offices, just
-; make these both the same
+; make these both the same.  Groups range from 0 to 63.
 ;
 callgroup=1
 pickupgroup=1