[cisco-voip] Problem with 7920 - ringing but no sound

[Konne]

hi @ all,

i have a little problem with my Cisco VoIP. I' ve a WLAN Infrastructure 
and i would like to implement VoIP now.
my problem is that the phones are communicating well, only that i can 
hear nothing.

have you any suggests

thx


my network:


Router2811 with DSP ----- TRUNK dot1q ------ Catalyst3750------------ ACS
                                                                         
                  |
                                                                         
                  |
                                                                         
            AP1240


                                                          ephone1 
7920                     ephone2 7920


my config Router2811:

router2811#sh run
Building configuration...

Current configuration : 2961 bytes
!
! Last configuration change at 11:52:04 MESZ Thu May 24 2007 by router2811
! NVRAM config last updated at 11:52:06 MESZ Thu May 24 2007 by router2811
!
version 12.3
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
!
hostname router2811
!
boot-start-marker
boot-end-marker
!
logging buffered 51200 warnings
!
clock timezone MEZ 1
clock summer-time MESZ recurring last Sun Mar 2:00 last Sun Oct 3:00
no aaa new-model
ip subnet-zero
!
!
ip cef
!
!
ip domain name +++++
ip name-server 192.168.138.10
ip name-server 192.168.138.11
no ftp-server write-enable
!
voice-card 0
 no dspfarm
 dsp services dspfarm
!
username +++++++ privilege 15 secret 5 ++++++++
!
!
!
!
interface FastEthernet0/0
 no ip address
 duplex auto
 speed auto
!
interface FastEthernet0/0.1
 description Management
 encapsulation dot1Q 1 native
 ip address 192.168.250.20 255.255.255.0
!
interface FastEthernet0/0.138
 description Server
 encapsulation dot1Q 138
 ip address 192.168.138.2 255.255.255.0
 no cdp enable
!
interface FastEthernet0/0.184
 description Admin
 encapsulation dot1Q 184
 ip address 192.168.184.2 255.255.255.0
 no cdp enable
!
interface FastEthernet0/0.880
 description VoIP
 encapsulation dot1Q 880
 ip address 10.95.180.5 255.255.255.0
!
interface FastEthernet0/1
 no ip address
 shutdown
 duplex auto
 speed auto
!
ip classless
!
!
no ip http server
ip http authentication local
ip http secure-server
ip http timeout-policy idle 60 life 86400 requests 10000
!
access-list 10 permit 192.168.184.0 0.0.0.255
access-list 10 permit 192.168.185.0 0.0.0.7
access-list 10 permit 192.168.250.0 0.0.0.255
!
!
!
control-plane
!
telephony-service
 max-ephones 10
 max-dn 10
 ip source-address 10.95.180.5 port 2000
 time-format 24
 date-format dd-mm-yy
 user-locale DE
 network-locale IT
 create cnf-files version-stamp 7960 May 23 2007 12:24:26
 max-conferences 8
 transfer-system full-blind
 transfer-pattern ...
!
!
ephone-dn  1
 number 750
!
!
ephone-dn  2
 number 751
!
!
ephone  1
 mac-address 0019.AAmac
 button  1:1
!
!
!
ephone  2
 mac-address 0019.AAmac2
 button  1:2
!
!
line con 0
 login local
line aux 0
line vty 0 4
 access-class 10 in
 exec-timeout 30 0
 privilege level 15
 login local
 transport input telnet ssh
line vty 5 15
 access-class 10 in
 exec-timeout 30 0
 privilege level 15
 login local
 transport input telnet ssh
!
scheduler allocate 20000 1000
ntp server 62.101.81.203 source FastEthernet0/0.138
ntp server 62.152.126.5 source FastEthernet0/0.138
!
end