Secondary terminal
Normally, a multipoint videoconference is not available unless the video and audio modes and transmission rate of the videoconferencing systems of all the sites are the same.*1 For a multipoint videoconference the terminal that can be connected in the same modes is called a primary terminal, while a secondary terminal is the terminal in which some of the functions are restricted since the connection is not enabled with the same modes. The restriction on the functions depends on the conditions described in “Notes on Secondary Terminals” under “Chapter 6 Multipoint Videoconference”.
For example, this system does not transmit video signals to a terminal that has no common formats but can communicate via audio signals. In this case, the terminal in which picture viewing is not available is regarded as a secondary terminal.*2 A terminal communicated via a normal phone included in the multipoint videoconference is also called a secondary terminal. For details on secondary terminals, see “Notes on Secondary Terminals” on page 149.
*1 Difference between the NTSC and PAL color systems is permitted.
*2 Receiving the video signals from this terminal may be available with the system.
SNMP
An abbreviation for Simple Network Management Protocol. This protocol is for management information between the management station and the managed terminals.
SPID
An abbreviation for Service Profile ID.
An identification number given to devices sharing a common ISDN line .
Terminal adaptor
A device used to connect various equipment to a digital line. The device sits between the equipment and the digital line and checks that signals are correctly sent or received.
182 Glossary