Supporting Phone Types in VOSS Phone Server

July 6, 2020

Keith Bareham, Director Solutions Engineering, VOSS Solutions

Announced last week, I wanted to dig a deeper into VOSS Phone Server, to give further insight into a standards-based SIP capability, offering registrar and SIP call handling services. This functionality allows SIP devices and soft clients to register with VOSS Phone Server in order to place and receive calls. Open standard support allows the use of SIP devices from any compliant vendor. This opens up a wide choice of phones offering various feature sets at various price points and allows the re-use of existing devices.

Setting up such phones requires the use of VOSS-4-UC as the UC management platform for VOSS Phone Server. VOSS Phone Server may be used as a standalone call control platform. When used in this mode, manual integration with other call routing devices such as SBCs or other PBX and trunking services is required. In its second ‘Cisco UCaaS (HCS)’, VOSS-4-UC manages the Cisco CUCM dial plan and trunking, removing the need for manual integration. Standard Cisco dial plan integration uses a dial plan templating facility. Other dial plans may be supported by creating custom dial plan templates suitable for the dial plan in use.

Adding Phones

Adding phones requires three areas of configuration. These are all automated by VOSS-4-UC during the phone addition:

1. Set up call routingIn HCS mode, the CUCM dial plan is created to provide call routing of the chosen numbers towards VOSS Phone Server. This allows incoming call routing. Outbound calling Class of Service and routing are also configured to allow internal extension and E164 call routing. Number inventory and CLI management through transformation patterns are maintained.
2. Set up the VOSS Phone ServerIn HCS or standalone mode, VOSS Phone Server is configured as a registrar to allow line registration of the chosen numbers. Since the server provides only registrar and SIP call handling capability, phone definitions are not required on the server. Representation of a phone is provided in VOSS-4-UC. A phone with two lines will appear as a single phone in VOSS-4-UC, but create two entries in the server; one for each line.
3. Configure the physical phoneThe phone itself requires configuration in order to register and handle calls. Soft clients will likely be manually configured locally on the hosting PC, and a “generic soft client” device type allows for locally configured devices. Other hardware devices such as phones from SNOM, Cisco and Grandstream may be configured using configuration files hosted on a centralized server and downloaded at start up by the phone. TFTP is used to download these files. VOSS Phone Server hosts such files for fully automated configuration of the device.

Adding phone types

New phone types (brands) can be created by creating a new phone type definition. This phone type defines behaviour of the GUI when adding a phone, and defines sample configuration files and configuration templates to apply to this configuration file. The sample file provides the layout of the phone configuration file but does not have values specific to each phone. Values such as the telephone number to apply are populated with a default value. The configuration template allows access to any parameter in the sample file, and can be used to set the correct value for each phone, such as setting the telephone number.

VOSS-4-UC has sample files and configuration for the SNOM D120 and D717 phones. This provides full configuration for these phones so that a new “out of the box” phone can be connected to the network and reach an operational state with no user intervention.

Adding a new phone type requires firstly creating a sample file. Many SNOM phones allow the export of the configuration which has been previously created through the phone web interface. This file can be used as the sample file, although values should be changed to make the file anonymous prior to uploading as a sample file. Once loaded, a configuration template can be created or cloned from the existing templates. This will allow modification of any value in the sample file, setting a value suitable for each phone.

Using this technique, new phones types may be evaluated and added to VOSS4UC without the need for software updates or patches.

To find out more about VOSS Phone Server please email [email protected].