Ring Intercom over LAN with IP protocol
Ring Intercom Systems that make an announcement by means of a loudspeakers network in order to search for a person and, successively, to start a conversation by means of an handset
Often, selective intercom systems are not suitable to be used because the people with whom you want to get in touch are not
in a fixed position but they move within the area served by the intercom system, therefore, it is not possible to use
selective intercoms systems.
For these cases ERMES developed a range of intercoms over LAN with IP protocol which adopt a different call strategy, these
systems are named "ring intercom systems".
"Ring intercom" refers to the old analog systems in which more twisted pair phone cables connect all the intercoms in
such way that one or more omnibus telephone lines (ring cable) are shared by all devices; on these basis, therefore, it is
possible to make a conversation between any pair of intercoms after they were connected on the same twisted pair (omnibus
telephone line).
In order to alert the person that you wish to contact, the analog intercoms have a further omnibus line (that is shared with
all intercoms) that drives an audio power amplifier with an external horn or loudspeaker.
In a ring intercom system in order to establish a conversation, you must first make an announcement on the horns inviting
the person with whom you want to talk to go to the nearest intercom and to start the talk by inserting the intercom on the
line pointed out by means of the announcement. The person who made the announcement must insert the intercom on the same
line and the conversation can begin.
ERMES developed a ring intercom system that emulates the operation mode described above by using only the
LAN connection between the intercoms.
In order to make the calls in "ring" operation mode, you can use both the hand-free intercoms and the handset intercoms
however the use of a handset intercoms is preferable because such devices allow you to perform, as well as conversations
between two locations, conversations between more equipment in order to have a conference with many users.
Basically, using the Ethernet network and the IP protocol, the system creates a virtual phone line on which are
connected in parallel all the intercoms between which the conversation takes place.
Even when you use intercoms that operate in ring operation mode, do not are present limits on the number of simultaneous
conversations that can be made at the same time by using different conversation lines; in fact, even in this case, the
intercoms involved in the call manage the communication directly, without the intervention of other equipment installed
in the system.
The call in ring mode as well as the call in selective mode is made by software entirely, consequently you can set an
intercom for mixed operation mode too and therefore the same apparatus can implement selective calls to certain intercoms
and ring calls to different intercoms.
The use of the Voice Over IP solution and the full programmability of the system allow you to make intercom systems over
LAN extremely flexible, by using existing Ethernet networks and without the need to lay complex and expensive cable networks
used exclusively for this service.
In fact, thanks to the LAN and the IP address that uniquely identifies each intercom, these ring intercoms can coexist
with other systems dedicated to different services; this connection technology allows you to expand the system with new
ring intercoms by simply adding over the LAN new intercoms with new IP addresses.
Phone +39 0438 308470 - Fax +39 0438 492340 - email: ermes@ermes-cctv.com
