X-lite is a SIP soft phone . it can work with CME using a config like below

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voice service voip

 allow-connections h323 to h323

 allow-connections sip to sip

 sip

  registrar server expires max 1200 min 300

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voice register global

 mode cme

 source-address 10.110.100.250 port 5060

 max-dn 20

 max-pool 8

 authenticate register

 create profile sync 0001250079101043

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voice register dn  2

 number 2824

 name Osama-sip

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voice register dn  3

 number 243

 name test

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voice register pool  2

 id mac 0000.0000.0011

 number 1 dn 2

 dtmf-relay sip-notify

 username osama password cisco

 codec g711ulaw

 no vad

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voice register pool  3

 id mac 0000.0000.0022

 number 1 dn 3

 dtmf-relay sip-notify

 username test password cisco

 codec g711ulaw

 no vad

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interface FastEthernet0/0

 ip address 10.110.100.250 255.255.0.0

 duplex auto

 speed auto

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dial-peer voice 1 pots

 destination-pattern 123

 port 0/0/0

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