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An interface and keypad emulator for Digital Security Control's PC1550Alarm Panel
This class is a keypad emulator for the Digital Security Control's (DSC)PC1550. The model number of the keypad it emulates is PC1550RK. Itshould work with any ATmega chipset, and was tested using an Arduino UNO.
- Title: PC1500-PC1550 user Author: Ron Webb Subject: PC1500-PC1550 user guide Keywords: PC1500, PC1550, 1500, 1550, DSC Created Date: 11/7/1999 1:20:04 PM.
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With this programmatic interface, you could emulate your own keypad onthe device (iPhone maybe?) of your choice. Or you could setup your ownmonitoring/alerting system (maybe send yourself a text message) when certainalarm events occur.
Hardware Connections
There are four wires that go to the keypad:
Red
Black
Yellow
Green
There is one additional connection that can be made that can provideadditional state information from the alarm controller.
Blue
See http://www.alarmhow.net/manuals/DSC/Modules/Output%20Modules/PC16-OUT.PDFfor a full listing of PGM options.
PC1550 Interface Specification
The PC1550 control panel starts by holding the clock high forroughly 26.5ms. It then clocks out 16 cycles (one cycle is representedby the clock going low and then returning to a high state). After16 clock cycles, the PC1550 holds the clock high for roughly 26.5msagain, which starts the entire cycle over.
During the 16 clock cycles data is received when the clock is high:
- The first 8 clock cycles are used to send one octet (byte)of data to the keypad (one bit per clock cycle). This bytecontains information about which zones are currently open(what zone lights should display on the keypad). For thisreason, the first 8 bits are referred to here as 'zone bits.'The table below shows how the data is received and interpretted.Bit 7 is received first, and bit 0 is recieved last. When bit 7is on, then the zone 1 light should be on; when bit 6 is on, thenthe zone 2 light should be on, etc. Bits 1 and 0 are not used.
- The second 8 clock cycles send 8 more bits. This byte containsinformation about the other lights that should be enabled onthe keypad. These bits represent other states and therefore,these bits are referred to here as 'state bits.'The table below shows how each bit is used. Note that when bit 0is on, the keypad beep emits a short beep.
State Bit 7 6 5 4 3 2 1 0Ready Armed Memory Bypass Trouble X X Beep
Between receipt of the zone bits, data can be sent back to the controlpanel when the clock is low. In other words, the panel sends out itsbits when the clock is high and the keypad sends back its data when theclock is low.
The keypad only sends back 7 bits-- one bit between each of the 8 zonebits received. These bits represent a button press. When taking thekeypad as a table (rows and columns) of buttons, the first threebits received represent the column of the button pressed. The lastfour bits represent the row of the button pressed:
Encoding bits in the data line:When the data line is LOW the corresponding bit should be ON.When the data line is HIGH the corresponding bit should be OFF.
If the PGM line is connected, then 16 more bits of data are receivedon this line if (and ONLY IF) the PGM line is configured in PC-16OUTmode. Refer to the PC1550 installation manual for instructions onhow to configure this mode. The bits meaning follow:
- 0 -- PGM Output (whatever the PGM is configured for)... (This library assumes PGM terminal has been programmed for... strobe output. This sets bit 0 to the on position... when the alarm goes off. And the bit remains set until... the panel is disarmed).
- 1 -- Fire buttom pressed (on for 4 sec)
- 2 -- Aux button pressed (on for 4 sec)
- 3 -- Panic button pressed (on for 4 sec)
- 4 -- Armed
- 5 -- Armed
- 6 -- Armed with bypass (on for 5 sec)
- 7 -- Trouble
- 8 -- Fire (on when fire alarm is latched in)
- 9 -- Not used
- 10 -- Zone 6 tripped while armed
- 11 -- Zone 5 tripped while armed
- 12 -- Zone 4 tripped while armed
- 13 -- Zone 3 tripped while armed
- 14 -- Zone 2 tripped while armed
- 15 -- Zone 1 tripped while armed
For the PGM terminal to work, it will need to be connected to theAUX+ terminal with a 1k Ohm resistor (for PC1550s)
Usage
To use the library, simply do three things:
The PC1550 object has a number of methods you may call to determine thestate of the lights on the keypad. All the following methods return a booleanvalue:
The PC1550 object has a number of methods you may call to determine thestate of the alarm based on the PGM output terminal. All the followingmethods return a boolean value:
There are a number of misc methods to provide additional details onthe state of the system:
You can simluate a keypress with the following method:
Dsc Pc1550 Installer Code 10
To read from the panel, call one of the following methods: