The state’s 911 operators will soon be able to receive emergency reports by text message. The Tennessee Emergency Communications Board voted unanimously Thursday to approve a pilot project led by AT&T. It sounds like a relatively simple advance in technology, but telecom companies have spent years trying to find a good way to send text messages to 911, and they still don’t have one. Tennessee will become the largest test case in the country. Smaller-scale systems have been implemented in Vermont and North Carolina where very few people used the service.