A citizen’s ability to send text messages to 9‐1‐1 emergency services (e.g., PSAP) is a topic that is undergoing significant discussions in the emergency services community, the people with disabilities community, and the wireless industry. The term “text” is used in the general sense during these discussions – “text” signifies everything from the short message service (SMS), to instant messaging (IM), to social networks such as Twitter and Facebook.
Understandably, the people with disabilities community in particular has expressed interest in text to 9‐1‐1 using the existing capabilities of their mobile devices, as an alternative to using bulky, cumbersome add‐on TTY devices. The wireless industry fully understands the desires of the people with disabilities community and is focused on finding a reliable solution for their needs. This analysis focuses on SMS as a means to contact 9‐1‐1 emergency services, with a goal to provide a view of the capabilities, limitations, threats and vulnerabilities of this means of communications. Texting, particularly SMS, has exploded in the past decade. Citizens rely on texting for their social communications needs. There are millions of SMS messages sent each day and there is a perception that SMS is reliable; however, SMS was never designed as a reliable means for life‐saving critical communications. SMS was designed to be secondary to voice calls and was never designed to provide the full and robust communications citizens have come to expect with voice calls. SMS has significant limitations and shortcomings that do not make SMS suitable for emergency communications, especially under life threatening conditions. It is important to understand that SMS is not and never will be a real time communications service. SMS by its very design is a non‐real‐time, best‐effort, store‐and‐forward service. SMS is not a session based protocol; without session based communications, SMS makes correlation of multiple messages from a citizen to a particular emergency impossible. With these characteristics, SMS messages may have a delayed delivery, may be delivered in a different order than the sender intended, or may be lost or discarded.
The purpose of this 4G Americas white paper is to examine the use of Short Message Service (SMS) messaging to 9‐1‐1 emergency services via Public Safety Answering Points (PSAPs). Read on.
