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There are variations (SH-42.2, SH-42.4, SH-42.6, and SH-42.8) with advanced firmwares that allows opening not only relays 1-2 but also 3-4, 5-6, and 7-8. This possibility is available only for panels with Linux OS. Configuration of lock opening (for relays 1-8) is only available via API. So, by changing the relays numeration in the system it is possible to connect up to 8 locks: SH-42.4 opens the 3rd and 4th locks, SH-42.6 works with the 5th and 6th, and so on. These locks opening is possible via DTMF and API. So, you must set a code (is possible via API). Locks 3,4,5,6,7,8 can be opened with the help of all monitor models, in the Intercom app and third-party applications/SIP clients. A user must open the keyboard (during a call) to enter the DTMF code(s) to unlock the required relay(s). This option is not currently available for the Link app. 
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Functionality
Two built-in relays to control two locks;
The ability to connect as electromechanical locks and latches and electromagnetic locks;
Switchable contact group on each relay;
Communication with the panel via RS-485 interface;
Input for control low-voltage analog signal;
Opening delay time configuration (for 8 pin module);
The ability to connect buttons for opening the first/second locks, and a fire alarm (for 8 pin module).