The University can notify all Penn faculty, staff and students via personal electronic devices (e.g., cell phones, PDA handhelds, smart phones, etc.) through text messaging, voicemail and email. The University also has Siren and Public Address systems in place to send a UPennAlert. The Penn Siren Outdoor System (Penn SOS) is comprised of 13 speakers transmitting voice intelligible emergency messages and alert tones to the outdoor campus environment.