Tetra Smart Solutions
DVI-100
The DVI-100 (Digital Voice Interface) will be attached to a Tetra Network in the same way as a normal Tetra terminal, and it can be a Member of up to 5 groups. When it receives a voice call, rather than decoding the digitally coded ACELP data stream into analog audio and feeding to the Loudspeaker, it is sent as a digital serial data stream to its RS-232 serial port. Connecting two DVI-100’s back-to-back with each device connected to a different Tetra network (which could be different infrastructure manufacturer, different frequency bands or geographically separated), allows the networks to be “interconnected” based on group calls. As the voice data stream is not converted back into and analog signal between reception by one DVI-100 and transmission by the second, the voice quality is not impacted by transmission between the 2 systems. As the serially transmitted ACELP voice data is received by the second DVI-100 and then sent to the second network, there will inevitably be a small time delay. To minimize the delay, the DVI-100 can optionally be directly connected to a Tetra Switch.
DVI-100 with IP-Connection
Optionally, the DVI-100 can also send and receive the ACELP Data via its Ethernet-Port using the UDP protocol. Using this option it is possible to send the digital voice data over IP, allowing long distances between the connected infrastructures; for example to connect a Tetra infrastructure to a Single Site Tetra system, or to use it as a "worst case backup" if the link (E1, IP, e.g.) between the Tetra Switch to the base station fails.
Connecting the iPhone or a Computer to the DVI-100
Using the DVI with IP, the voice data can easy be sent to, or received from, a remote application, potentially running on any type of device. This allows the voice call to be bridged between the Tetra infrastructure and another device. An iPhone application is available, as well as Java based software for Mac or Windows Computers. This application can be useful, if a user needs to talk or just listen to a group within a Tetra network, even when they are out of coverage of the Tetra network.
