HSA6200 is the basic alarm with no control panel, all the electronics are inside the bellbox. Sadly, the bellbox cannot transmit to another siren. It only receives signals from the other components.
I was quite puzzled the first time I tried to do what you have in mind, because I had not grasped the different way the control panel system works with the same accessories.
If you can afford an HSA6400 (they are sometimes on special offer) it includes a control panel which can be linked to your existing components, and a siren, so you can use it as well as the one you already have, and more sensors.
Or, you may find, on ebay or similar, an HSA6400 control panel, but they are not cheap because lots of people, like you, want to get one. You also have the risk that a second-hand one may not work. I forget the maximum number of sensors you can fit, but it is more than a large house needs. There is no limit to the number of sirens you can add.
You can buy a new control panel on itds own
https://www.yalestore.co.uk/hsa6400-control-panel.html but it is better value to buy the entire kit.
The HSA6400 kit contains the same siren as you already have, but the siren is used as a passive receiver, it receives all its signals from the control panel, not the sensors and keypad. This is done during the setup. The control panel is the only component that both sends and receives.
The panel allows you to do part-set for night time, gives an audible countdown, and has a fault log display.
You could also use a HSA6300 control panel, which is the same but does not have the dial-out function to phone you or keyholders, so is not quite as good. It is even possible to add older models of control panel, I have done this, but it is a bit awkward because you have to use both books of instructions, the new one for your new devices and the old one for your old panel. Linking the remote keypad took me several attempts.
HSA6200 components
HSA6400 components
There is also a rectangular siren box that contains the same electronics inside as the round one.
The HSA6400 is IMO quite a good product if you need a low-cost DIY system that you can fit yourself in a couple of hours. Its best feature is the dial-out phone link. It is very simple and does not rely on internet or smartphones. If you have a rental property you can unscrew the components and take them with you when you move. Of course, you can buy better if you spend more. Professional installers often sneer at it. A skilled burglar with the right equipment can interfere with the wireless signal, but round my way, most burglars are 14-year-old coke heads who have difficulty following the instructions for a tin-opener.
