The speed limits in Bosnia are 50 km/h (31 mph) in built up areas, 80 km/h (50 mph) outside built up areas, and 130 km/h (81 mph) on motorways.
In Bosnia the motorways are numbered and prefixed with the letter A, the non motorway main roads are numbered and prefixed with the letter M, the smaller roads are numbered and prefixed with the letter R.
The Bosnian motorways and the non motorway main roads that I rode on are of a good standard, the condition of the smaller roads are generally good but there is always the odd exception.
Like most countries in the Balkans, the motorways signs have a Green background with White numbers for the motorway number, the non motorway main road signs have a Blue background with White numbers, and signs for the smaller roads have a Yellow background with Black names.
Bosnia are not in the EU so they still have their national borders and depending on what insurance policy you have for your bike you may be required to purchase insurance for it at the border. They also do not use the Euro in Serbia and petrol at the time of writing was the equivalent of about 1.40 Euros per litre.
I never saw any signs for speed cameras and I never saw any patrolling police vehicles.
My personal experience of biking in Bosnia was that it had very few roads that I enjoyed riding in. Only once I approached the border with Croatia did the roads get more to my liking.
I did not buy a SIM card for a mobile phone whilst I was in Bosnia so I have no information about how to do this.