Signal Transmission
and Alarm Receiving Centres
Many fire alarm systems in the UK are monitored remotely by an Alarm Receiving Centre — a staffed facility that receives the alarm signal and alerts the appropriate emergency service. Understanding what monitoring provides, and what it does not, helps you make an informed decision about whether it is right for your premises.
Alarm Receiving Centres Explained
An Alarm Receiving Centre (ARC) is a permanently staffed facility that receives electronic alarm signals from fire alarm systems, intruder alarms, and other security systems at monitored premises. When a fire alarm signal is received, ARC operators follow a defined protocol — typically confirming the signal is genuine and then alerting the Fire and Rescue Service.
ARCs are certified to BS 5979 (Category II for fire alarm receiving) and operate 24 hours a day, 365 days a year. The largest ARCs in the UK handle signals from hundreds of thousands of premises simultaneously.
What Monitoring Does — and Does Not — Provide
Remote monitoring ensures that if your fire alarm activates when the building is unoccupied — or when occupants cannot reach a phone — the Fire and Rescue Service will still be alerted. What it does not provide is a guarantee of Fire Service response to every alarm. The Fire and Rescue Service has discretion over how it responds to monitored alarms, and some services have moved to a policy of requiring confirmation of fire before responding to certain premises, particularly those with a history of unwanted alarms.
Transmission Standards
Signal Transmission Grades — BS 8521
BS 8521 is the British Standard that specifies the requirements for alarm transmission systems used to transmit fire alarm signals to ARCs. It defines different grades of transmission based on the reliability and redundancy of the communication path.
| Grade | Description | Typical Application |
|---|---|---|
| Grade 1 | Single transmission path — typically a broadband internet connection or GSM/GPRS. If the path fails, no signal reaches the ARC until it is restored | Lower-risk premises where monitoring is desired but the highest level of resilience is not required |
| Grade 2 | Dual transmission path — two independent communication paths used simultaneously. If one path fails, signals continue via the other. The ARC is also alerted if communication is lost | Most commercial premises where continuous monitored protection is required — the most commonly specified grade |
| Grade 3 | Enhanced dual path with additional supervision and faster polling — provides higher assurance that any loss of communication is detected and reported very quickly | Higher-risk premises, premises where insurers specify enhanced transmission, critical infrastructure |
| Grade 4 | Highest level — dedicated communication path with very high supervision frequency. Typically reserved for the highest-risk applications | Very high-risk premises, government or critical national infrastructure |
Transmission Methods
How Signals Are Transmitted
IP (Internet Protocol)
Alarm signals are transmitted over the building’s broadband internet connection to the ARC. Low cost and widely available, but reliant on the internet connection being available. For Grade 2 and above, a secondary path (typically GSM) is used alongside IP.
GSM / GPRS
Signals are transmitted via the mobile phone network using a SIM card in the alarm communicator. Provides network diversity from IP — a broadband failure does not affect GSM transmission. Used as the secondary path in most dual-path systems.
PSTN (Telephone Line)
Traditional transmission over the public switched telephone network. Being phased out as BT and other providers migrate to IP-based networks — the PSTN switch-off in the UK means PSTN-based alarm transmission will cease to function and must be upgraded.
Dedicated Digital Communicator
Purpose-built alarm transmission equipment using dedicated or managed network paths for the highest-grade applications. Provides the most reliable and tamper-resistant transmission but at significantly higher cost.
The PSTN Switch-Off — Action Required
BT and other telecoms providers are decommissioning the traditional copper telephone network and migrating all services to IP. This process is ongoing and will affect any fire alarm or intruder alarm system that uses a PSTN telephone line for transmission to an ARC. If your monitoring system uses a traditional phone line, you need to arrange an upgrade to IP or GSM-based transmission before your area is migrated. Your alarm maintenance contractor should be advising you on this — if they have not, raise it at your next service visit.
Cost and Contracts
What Does ARC Monitoring Cost?
| Cost Element | Typical Range | Notes |
|---|---|---|
| ARC monitoring contract | £150–£600 per year | Varies by grade, premises type, and number of signals. Higher-grade transmission and larger premises attract higher fees |
| Alarm communicator equipment | £150–£500 per unit | One-off cost for the transmission hardware installed at the premises |
| Installation and commissioning | £100–£300 | Labour to install and commission the communicator and register with the ARC |
| SIM card (for GSM path) | Included in contract or £50–£100 p.a. | Depending on the ARC contract structure |
| False alarm charges | Varies | Some ARCs charge for excessive unwanted alarm activations — check contract terms |
Do You Need It?
Is ARC Monitoring Required for Your Premises?
Remote monitoring via an ARC is not a legal requirement for most premises under the RRO 2005. However it may be required or strongly recommended in a number of circumstances:
Insurer Requirement
Many commercial property insurers require ARC monitoring as a condition of cover for unoccupied or high-value premises. Check your policy conditions carefully — absence of monitoring where required can invalidate a claim.
Unoccupied Periods
If your premises are regularly unoccupied overnight or at weekends and no other means of detecting and reporting a fire exists, ARC monitoring is the most reliable way to ensure the Fire and Rescue Service is alerted promptly.
Sleeping Risk Premises
For premises where people sleep — hotels, care homes, HMOs — ARC monitoring is strongly recommended and may be specified by the fire risk assessment as an appropriate control measure.
Fire Risk Assessment Recommendation
If your fire risk assessment has identified ARC monitoring as an appropriate fire precaution for your premises, it should be treated as a requirement rather than an optional extra.
Further reading
Questions about monitoring your system?
Whether you are setting up monitoring for the first time, upgrading from PSTN, or reviewing your current ARC contract, get in touch for straightforward independent advice.
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