Scoring units would usually be android smartphones or android tablets, but can be other touchscreen phones/tablets that have a web browser (e.g. iPhone/iPad). A mobile network connection is not required, only wifi support. Manufacturers are continually bringing out new models, so any specific recommendation made here would soon be out of date, However, even a low end device will suffice. The BridgePal app will run on any android version from 3.0 upwards.
We have recently (in 2016-2017) purchased a number of Alcatel Pixi 4 4" phones, running android 6.0, from various sources at prices ranging from 20 to 35 pounds per phone. These have proved excellent for the application, and a number of clubs using BridgePal have also purchased this model.
An expensive high performance model is not necessary. For our local club we purchased an Asus RT-N12 router, which proved easily capable of handling 22 connected android phones. As the bandwidth requirements are low, even an old wireless-g router would be adequate from this point of view providing that it can support the required number of connected devices. Make sure that all the smartphones or tablets and the PC also support the chosen wifi standard (g, n or later).
A PC running Windows is required to host the scoring program and interface to the scoring units via wifi. Any version of Windows from XP (Service Pack 3) onwards is suitable. The hardware requirements are minimal, and even the cheapest new windows laptops are adequate for the task. Alternatively, rather than purchasing a new PC or tablet, it may be possible to use an old second hand laptop which is no longer considered to have adequate capacity or performance for other use.