Signal 21 Security Systems, Inc. offers 24-hour U.L. listed monitoring for burglar alarm systems and fire alarm systems, security cameras, video surveillance systems, annual fire alarm system inspections as required for most commercial fire alarm systems, security system repair and maintenance for most burglar alarm and fire alarm systems, as well as stock batteries for most burglar alarm systems. Signal 21 only installs non-proprietary equipment. Most mass marketing Alarm Companies install proprietary equipment, which locks you into that single company for all your future alarm needs. You can?t get service or monitoring from any other company without purchasing new equipment. This is very important to consider from a consumer viewpoint. Signal 21 does not require that you sign a long term monitoring contract. We offer high quality, low cost 24 hour U.L. Monitoring service for burglar alarms with low monthly fees. If monitoring service is not requested, no monthly fees will be necessary.