SilentKnight VisorAlarm Plus 2U - Manual (Page 8)

VISORALARM - Introduction
I - 6
Doc.DM374-I
Ver. 1.0
3. Operating Mode
The IP Mode (mIP/IPDACT) connected to the client control panel carries out two tasks:
1) Capture the alarms sent by the control panel and send them over the IP network to which it is
connected. These alarms are then received by the Teldat VisorALARM PLUS 2U in order to
be sent to the corresponding automation software (SwAut).
2) Generate monitoring traffic so that both ends of the security environment check the IP
connectivity, as it is this that permits the above task to be carried out.
3.1. Monitoring
The mIP/IPDACT is a device that intercepts the control panel telephone connection with two aims:
firstly to detect when the panel sends an alarm in order to capture it and retransmit over the connected
IP network and secondly to allow the telephone line to be used at the same time as sending alarms.
The interception of the telephone line takes place ONLY in cases where connectivity with the Teldat
VisorALARM PLUS 2U has been verified. The mIP/IPDACT - VisorALARM PLUS 2U connectivity
is checked through a traffic monitor which the mIP/IPDACT periodically sends and to which the
Teldat VisorALARM PLUS 2U responds. If this exchange of messages does not occur during the
configured time, the mIP/IPDACT tries to resend. If, after a configurable number of attempts
(between 1 and 9), a satisfactory response is not received, the connectivity is presumed lost. The time
between polling messages is programmable between 0 and 90 seconds, a typical value being 15
seconds. The time between retries is also configurable, between 3 and 9 seconds.
If a network backup scheme is running, the mIP/IPDACT has a second IP receiver to establish
communications and send alarms. If this second receiver does not respond to the communication
established with it by the mIP/IPDACT (again after a configurable number of attempts), the telephone
line access is returned to the control panel as if the mIP/IPDACT is no longer operative at the alarm
level. From this point on, the mIP/IPDACT will try to re-establish communications with both the
main Teldat VisorALARM PLUS 2U as well as the backup, if there is one. As soon as this is re-
established with either of the two VisorALARM PLUS 2U, the mIP/IPDACT will once more intercept
the telephone line.
The monitoring traffic is encrypted UDP traffic. The Ethernet frame size does not exceed 70 bytes.
The monitoring interval, the number of retries and time between retries are all configurable, both for
the main VisorALARM PLUS 2U as well as for the backup. The time between retries is an important
parameter as it influences the global traffic supported by the VisorALARM PLUS 2U (polling over all
the devices). You also need to bear in mind that polling is a tool to control the state of both the alarm
reception center and the mIP/IPDACT. A long interval between polls can give rise to situations where
the VisorALARM PLUS 2U delays in detecting a problem with the mIP/IPDACT and consequently a
problem in a client. Finally, if the mIP/IPDACT accesses Internet via a device which executes NAT,
traffic coming from the VisorALARM PLUS 2U (configuration for example) will not reach the
mIP/IPDACT if the period between polls is inferior to the outgoing router NAT tables refresh time (a
typical refresh value is 5 minutes).
The Teldat VisorALARM PLUS 2U received monitoring messages from the mIP/IPDACTs. If these
are registered, they are assumed alive and an acknowledgement response is sent to them; if the
mIP/IPDACTs are not registered, they are ignored. Periodically the status of all the registered
mIP/IPDACTs is checked and an alarm is generated for all those which have not notified their
availability (i.e. those which have not responded since the last check). This is a 350 code alarm from
the Contact-ID protocol (Communication trouble) which is received in the SwAut. From release
10.1.27 onwards, the event code is configurable. Default is 350. As each mIP/IPDACT can have a