The numeric-only PIN, also known as a Passcode, is required for the SafetyLine Voice App, and for Monitors to acknowledge emergencies via phone/keypad.
To change your PIN, log into SafetyLine via https://slmonitor.com/Login, then click on the Profile tab.
Scroll down to the "Voice App Login" section, and select "Reset Passcode".
Generate a random passcode or enter your own, then enter it once more before selecting "Save."