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The connections should ideally be made with 4 core alarm cable, which will fit tidily into the sensors. Alternatively you could use any convenient thin two core cable. Hide the cable out of sight where possible.

The loop cable should be threaded through or attached to the items to be protected. For example, with bicycles thread the cable through both wheels and the frame.

Some items, such as televisions and hi-fi equipment have no obvious gaps to thread the cable through, and will therefore call for some ingenuity. If you are sure you know what you are doing, and the item is out of guarantee, you may be able to remove the back or cover and thread a piece of cable through a couple of the ventilation slots before fitting plugs to the ends. Alternatively you could fix a section of the cable to the item with a suitable adhesive such as Araldite.

If you don't want to mark the item, the best option might be to securely tie the loop cable to the units mains cable. A few cable ties can be useful here. Another possibility is a P-clip under a suitable screw on the unit.

External Alarm or Sounder
The relay contacts may be connected to an additional sounder or a separate household alarm system if required. The additional sounder may be a similar type to that used in the unit, mounted in an outdoor enclosure and powered by it's own battery.

The unit may be connected to any convenient zone on an alarm panel, depending on the type of protection required. The Panic button input would be suitable if you wish the alarm to operate whether or not the main alarm is set. If you have a monitored alarm system you may need to contact the monitoring company before connecting this unit to the system.

Greater Tamper Resistance
No alarm system is 100% secure and completely resistant to any attempt to defeat it, and this unit is certainly no exception. However it should be adequate in most cases.

The following suggestions are offered to more experienced constructors who may wish to customize their system and installation to suit their individual circumstances.

If the unit is connected to an external alarm system, as described earlier, this will continue to sound if an intruder attempts to smash this unit once it has triggered.

The main concern will probably be attempts to defeat the unit to prevent it being triggered. Normally this would involve trying to bypass the loop, close to the alarm unit, so that it may be disconnected. The system operates by sensing the resistance of the terminating resistance via the loop. This resistance need not be a single component at the far end, it could be made up of a number of resistors along the loop.

If R5 is reduced to 33K, and two additional 33K resistors are added inside connection plugs along the length of the loop, any attempt to bypass the loop at the alarm end would trigger the unit. I would suggest that one of the additional resistors is in the core connection and the other is in the screen. The only drawback of this is that you have to remember to use all the pieces of loop cable, but this could be ensured by using a different type of connector for each joint. You could use any number of resistors, providing the total resistance is between 90K and 110K.

The other likely tampering method would be to disassemble the box and disconnect the battery. This could be sensed by either a tilt switch or micro-switch suitably positioned within the box. The micro-switch would be held operated by the lid, such that it is released when the lid is removed. Fix it inside the case with glue, as the screw-heads on the outside of the box would be a give-away! In either case the connections that are closed when everything is OK are connected inseries with the Loop connections inside the box.