Test yourself: how much do you know about international communications? (International numbering systems)

We like to think of international telephone communications as 'transparent', the successful outcome of 100 years of technical progress and standards setting, but the author shows us that it is not. The user still has to be something of an expert to understand how to make international calls, and there are chaotically differing numbering systems for telephony, telex, and electronic mail. We should be reminded that usability of services, not just their usefulness, is a critical component of communications. Simplicity, consistency, and rationality of service features and the 'human interface' that allows users to invoke them should be a high priority for communications engineers as they work toward the integrated services networks of the future. >