Every country had different types of coins with different values and they were not easily comparable in value with the money from the other countries. This could have been fixed with collaboration between neighboring countries from certain areas to create same types of coins that have the same value so that they can use them easily for the trade that was occurring between the different economies.
Every craftsmen that had the skills and tools and suitable material was able to create copies of the money. This could have been fixed with strict regulations on every craftsmen by the authorities. Also putting a unique mark on the different types of coins by the official producers that was not easy to be copied.
Early forms of money was made up of such things which were easily available and so the currency could be copied. It was difficult to compare two different places currency values.
Bank customers should reconcile their records frequently with bank statements to prevent their checks from bouncing. They should frequently check the record of their balance in the account and the transactions being made to make sure that th checks they issue will still be valid.
A group of such computers - which get interconnected in order to share information or documents are usually called a computer network. This is a common type of networking when working in large companies or businesses.
