6.1.3 OperationNoteFor devices connected to a PBX other than the Main Unit, refer to the Troubleshooting for that PBX.PROBLEM PROBABLE CAUSE SOLUTIONCannot set the IP address,subnet mask address, andPBX IP address to the SIPPhone.• An unusable value isbeing set.• Set an IP address within the valid range. IPaddress of the SIP Phone/PBX: "1.0.0.0" to223.255.255.255 Subnet mask address: 0–255.0–255.0–255.0–255 (except 0.0.0.0and "255.255.255.255")Cannot register the SIPPhone.• The necessarynetwork parametersare not set to the SIPPhone.• When not using the DHCP Server feature oran external DHCP server, set the IPaddress, subnet mask address, and enterthe PBX IP address. If necessary, also enterthe IP address of the default gateway.• When using the DHCP Server feature or anexternal DHCP server, enter the PBX IPaddress.• Automatic registration is only compatiblewith KX-HDV series connected to the samenetwork as the KX-HTS series LAN port.The SIP Phone cannotconnect to the PBX.• The wrong IP address,subnet mask address,PBX IP address, ordefault gatewayaddress was entered.• Check each parameter and enter thecorrect value.• The Ethernet cable isnot connectedcorrectly.• Check the Ethernet cable connections.• The DHCP server isnot active.• Restart the external DHCP server.• Confirm whether the DHCP Server featureis enabled.• Disable DHCP and re-enter settings asappropriate.The SIP Phone does notring.• The ringer volume isoff.• Turn on the ringer volume.6.1.3 OperationGetting Started 109