Response 3

FCC ID: JE4RWSAL433

Cover Letter(s)

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FCCID_940492

March 13, 2008 American TCB 6731 Whittier Ave Suite C110 McLean, VA 22101 Attn: Mr. T. Johnson, Examining Engineer RE: your e-mail dated March 12, 2008; Risco Ltd. FCC ID:JE4RWSAL433, ATCB005951 3rd Reply to ATCB remarks for WisDom panel 1) Will be dealt with in the JE4RWRT433 process. 2) We have shown that only 3 possible events can cause transmission, and since two of them are alarm (see explanation in 3, tamper is 100% alarm) then they have no time limitation what so ever and so all repetitions are still in the status of alarm, and we need not comply with any 15.231 requirements (not the 5 sec and neither the 2 sec). So the only applicable situation is initialization, and that can only be done in two cases: - iInstaller install the panel for first time - for the user to cause this, he must unplug the AC voltage then wait for the battery to run out (should take around 13h) and then plug the AC back in, and this will cause the system to initialize again. So the worst case is still one initialization per hour, which is 8 repetitions in worst case, which is 200 ms in an hour. This does not justifying making a counter to limit for 2 sec, there cannot be an evaluation of the 2 sec limit. www.riscogroup.com

3) The interpretation of tamper stated above is wrong for two reasons: a) Related generally to tamper behavior in alarm systems tamper is a 100% alarm condition. It is true that this is a special alarm, but nevertheless it is an alarm. Also a tamper is not limited to armed system, the contrary is the case. When a system is armed, it will be hard for you to approach a unit undetected since every detector will trigger alarm. Tamper will work in arm mode but the main goal of tamper is to make an alarm in unset mode, since it is easy to approach an unset system, to tamper with it so it will not work properly, and then to return when the system is armed and use the advantage created. To summarize, a tamper will cause alarm in both set and unset mode. b) In the specific unit we are discussing, there is another important point. The transmission sent to the siren in the case of alarm event is to start the bell and sound the alarm. So the event is the "Alarm" but the message actually says: "start making noise". Now what we call tamper is event only differ in the event, meaning the cause of the message is not spotting someone in a detector, but is due to tampering with the panel or with other components in the system. So the trigger is different (tamper vs alarm) but message is the same, and therefore the siren gets a "make noise" message in either case. So tamper shall be associated with alarm requirements, and therefore 15.231 timing requirements shall not apply to it. Sincerely, Efi Goren, Certification Engineer Risco Ltd. www.riscogroup.com


Document Created: 2008-03-13 10:23:57
Document Modified: 2008-03-13 10:23:57
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