Voice over IP (VoIP) VoIP System Telephones127OpenCom 510 checks the MAC address sent with the registration and confirmsthe registration request if the VoIP system telephone is listed in the menuPBX Configuration: Devices: VoIP Phones. The keep-alive time, port number(8101) for telephony signalling and the value to use for the TOS byte are alsocommunicated in the registration answer.6. The VoIP system telephone creates a second TCP connection using the sig-nalling port number 8101 and sends a registration analogue to the U pn systemtelephones.7. Extra connections are created using the IP protocol RTP (“Realtime TransportProtocol”) for call data when a call is created. For calls between two VoIP systemtelephones, port numbers above 8200 are used. For transmission to a MediaGateway card, a port in the range 1024 – 1087 is used.If you wish to operate a VoIP system telephone via a routed IP connection (forexample VPN or RAS) it may be necessary to configure an external DHCP serveraccordingly. Please note the selection of the codec and keep-alive time for RASconnections. This can be done by selecting the default profile RAS in thePBX Configuration: Devices: VoIP Phones for the VoIP system telephone. Theoperations software provided via TFTP must match the type of device and com-munication system. You may also need to configure BOOTP, DHCP and TFTPservers for the VoIP system telephone.10.5.5 Local ConfigurationIn addition to automatic configuration via BOOTP/DHCP, it is possible to manuallyconfigure an OpenPhone 73 IP or an OpenPhone 75 IP. This can make sense, forexample, when you wish to connect a VoIP system telephone at a distant locationvia router. This local configuration is saved permanently in the non-volatilememory of the VoIP system telephone. To change the local configuration, use anadditional programme, the Java-based “IP Phone Configurator”.Note: Java programmes can be run on all common operat-ing systems. To execute Java-based programmes, you mustinstall a suitable Java runtime environment on your operat-ing system (JRE). This can be downloaded under the follow-ing web address: http://www.java.com/.
