Do not work on your telephone at all if you wear a pacemaker.

Telephone lines carry electrical current. To avoid contact with electrical current:
• Use a screwdriver or other tools with insulated handles.
• Do not touch screw terminals or bare conductors with your hands.

Although the lines are grounded, do not open the Network Interface Device (NID) or test the lines during rain, a thunderstorm, other hazardous weather conditions, or if there is water pooled on the ground near the NID.