Tablet computer as user interface of security system

A building security system comprising:

• a security sensor configured to sense a security breach associated with a building;
• and
• an off-the-shelf portable personal electronic computing device communicatively coupled to the security sensor and to a central monitoring station, the computing device being configured to:
• perform security functions including transmitting an alarm signal to the central monitoring station in response to the security sensor sensing a security breach associated with the building;
• and
• perform a non-security function comprising word processing, electronic mail, electronic instant messaging with another personal electronic computing device, capturing photographic images, interpreting user writing with a stylus on a touch-sensitive screen, and/or internet browsing.

A building security system comprising:

• a plurality of security sensors configured to sense a security breach associated with a building;
• and
• an off-the-shelf portable personal electronic computing device communicatively coupled to the security sensors and to a central monitoring station, the computing device being configured to:
• perform a plurality of security functions including transmitting an alarm signal to the central monitoring station in response to at least one of the security sensors sensing a security breach associated with the building;
• and
• perform a plurality of non-security functions including word processing, electronic mail, electronic instant messaging with another personal electronic computing device, capturing photographic images, interpreting user writing with a stylus on a touch-sensitive screen, and/or internet browsing, wherein the computing device assigns higher priority to each of the security functions than to any one of the non-security functions such that the computing device performs each pending said security function before performing any pending said non-security function.