Here is my simple configuration of Call Manager Express version 4.0 running IOS 12.4(9) in Router ISR 2801:
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telephony-service
no auto-reg-ephone
max-ephones 5
max-dn 10
ip source-address 192.168.88.5 port 2000
system message CISCO VOICE LAB
time-format 24
web admin system name webadmin secret 5 cisco123
dn-webedit
time-webedit
create cnf-files
!
ephone-dn 1 dual-line
number 5060
!
ephone-dn 2 dual-line
number 5061
!
ephone-dn 3 dual-line
number 5062
!
ephone 1
mac-address 000C.DE34.AAAA
type CIPC
button 1:1
button 2:3
!
ephone 2
mac-address 000C.220E.BAAB
type 7941
button 1:2
!
!
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done...