[Asterisk-Users] cisco 3620 setup (newbie cisco alert)

[Asterisk]

I'm experimenting (using for the first time) with using a cisco3620 to 
connect to the PSTN via a channelised E1 interface, with * handling all 
of the SIP calls.

If anyone has any installation tips / help / documentation I would be 
most appreciative :)

However, my first question is this: when I am in the setup, I see the 
following:

Current interface summary

Controller Timeslots D-Channel Configurable modes Status
E1 0/0     31        15        pri/channelized     Administratively up
E1 1/0     31        15        pri/channelized     Administratively up

I have set both controllers to hdb3, ccs with crc4

I notice that the D-Channel is set to 15. However, in the zaptel.conf 
file I use with my TE410p card, the D-Channel is set to 16. So, is cisco 
counting 0-14 (hence 15 is the D-Channek) and zaptel counting from 1-15 
(and therefore 16 is the D-channel) ? Or is my config wrong on the cisco 
or zaptel ??

Any help would be welcome. Thanks !

Julian