Cisco Systems 7940G Manual De Usuario

You should verify the IP addressing and routing settings on the phone. If you are using DHCP, the DHCP 
server should provide these values. If you have assigned a static IP address to the phone, you must enter 
these values manually. 

On the Cisco Unified IP Phone, press the Settings button, choose Network Configuration, and look at 
the following options:

DHCP Server—If you have assigned a static IP address to the phone, you do not need to enter a value 
for the DHCP Server option. However, if you are using a DHCP server, this option must have a value. 
If it does not, check your IP routing and VLAN configuration. Refer to Troubleshooting Switch Port 
Problems, available at this URL: 

IP Address, Subnet Mask, Default Router—If you have assigned a static IP address to the phone, 
you must manually enter settings for these options. See the 

 for instructions.

If you are using DHCP, check the IP addresses distributed by your DHCP server. Refer to Understanding 
and Troubleshooting DHCP in Catalyst Switch or Enterprise Networks, available at this URL: 

If you are using DNS to refer to the TFTP server or to Cisco Unified Communications Manager, you 
must ensure that you have specified a DNS server. Verify this setting by pressing the Settings button on 
the phone, choosing Network Configuration, and scrolling to the DNS Server 1 option. You should also 
verify that there is a CNAME entry in the DNS server for the TFTP server and for the 
Cisco Unified Communications Manager system.

You must also ensure that DNS is configured to do reverse look-ups.

On the Cisco Unified IP Phone, press the Settings button, choose Network Configuration, and look at 
the Communications Manager 1–5 options. The Cisco Unified IP Phone attempts to open a TCP 
connection to all the Cisco Unified Communications Manager servers that are part of the assigned 
Cisco Unified Communications Manager group. If none of these options contain IP addresses or show 
Active or Standby, the phone is not properly registered with Cisco Unified Communications Manager. 
See the 

 for 

tips on resolving this problem.

If the Cisco Unified Communications Manager or TFTP services are not running, phones may not be 
able to start up properly. However, in such a situation, it is likely that you are experiencing a system-wide 
failure and that other phones and devices are unable to start up properly. 

If the Cisco Communications Manager service is not running, all devices on the network that rely on it 
to make phone calls will be affected. If the TFTP service is not running, many devices will not be able 
to start up successfully.