Alarm Communicator and SIM Module Guide¶

Guide to alarm communicators and SIM modules for UK alarm systems covering 4G backup, dual-path signalling, ARC monitoring, and failsafe communication for Grade 2 and Grade 3 compliance.

Alarm Communication Methods for UK Systems¶

Alarm communicators are the link between your alarm system and the outside world, sending alerts to your smartphone and the Alarm Receiving Centre (ARC). UK alarm communicators fall into three categories: landline PSTN dialler (legacy, being phased out as BT switches off the PSTN network by 2027), 4G cellular module (most common, using Vodafone/EE/O2 networks), and IP/ethernet communicator (using broadband connection). For Grade 2 compliance, a single communication path (4G or IP) is sufficient. Grade 3 requires dual-path signalling - typically 4G plus IP, or dual-SIM 4G. Popular UK communicators: Texecom SmartCom (£80-£120, dual-path 4G+IP, app control), Pyronix CloudLink SE (£70-£100, 4G, cloud monitoring), Ajax Comms Module (£50-£80, 4G with Jeweller protocol), and Risco WiComm Pro (£90-£130, dual-path 4G+IP). 4G modules require a SIM card - either included with monitoring contract (£5-£15/month) or a standard UK PAYG SIM (Vodafone or EE recommended for coverage). The 4G module draws 3-5W and should be positioned near a window for best signal - check coverage on Ofcom's mobile coverage checker before installation.

Installation and SIM Module Configuration¶

Step 1: Choose the communicator location - near a window for best 4G signal, or near the router for IP connection. Avoid metal cabinets and basement locations. Step 2: Connect the communicator to the alarm panel via the data bus (typically 4-core cable for Texecom Digibus or Pyronix serial bus). Step 3: Insert the SIM card - ensure it is unlocked for any network (use EE, Vodafone, or O2 in order of UK coverage reliability). Step 4: Power up and wait for network registration - the communicator LED shows network status (slow flash = searching, solid = connected). Step 5: Configure the ARC monitoring parameters: set the account number provided by your ARC, set the reporting format (SIA DC-09 or Contact ID are UK standards), set Primary and Secondary phone numbers for dual-path systems. Step 6: Test end-to-end by triggering the alarm and confirming the ARC receives the signal. Step 7: Configure smartphone app notifications (push alerts for arm/disarm, alarm, tamper, and low battery). Step 8: Set automatic weekly test transmissions. For broadband-only communicators, ensure the router has battery backup UPS - a small 600VA UPS costs £50-£80 from Amazon UK and keeps the router running for 30-60 minutes during power cuts.

Specifications and Comparison¶

Communicator Type	Paths	Monthly Cost	Grade	UK Price
PSTN Landline	Single (phone line)	Included with line	Grade 2	£40-£60
4G Cellular	Single (mobile network)	£5-£15/month SIM	Grade 2	£60-£120
Dual-Path 4G+IP	Dual (4G + broadband)	£10-£20/month	Grade 3	£80-£130
Dual-SIM 4G	Dual (two mobile nets)	£10-£15/month	Grade 2+	£90-£140
IP Ethernet	Single (broadband)	No SIM cost	Grade 2	£40-£80

FAQ¶

Do I need a communicator for my alarm?: Yes if you want remote smartphone control, push notifications, or ARC monitoring. A 4G communicator with the app provides remote arm/disarm and instant alerts without monthly ARC fees. ARC monitoring costs £10-£25/month.
Which UK mobile network works best for alarm communicators?: EE and Vodafone have the best UK coverage for alarm communicators. Check Ofcom's mobile coverage checker at the installation location before purchasing. Dual-SIM communicators using both networks provide redundancy.
Will my alarm still work if BT switches off the PSTN line?: Yes - upgrade your communicator to 4G or IP before the PSTN switch-off in 2027. Most UK alarm companies offer PSTN-to-4G upgrade programmes. Contact your alarm provider to schedule the upgrade. For more information see our Wired Alarm Sensor Installation Guide.

Last updated: 2026-05-31.

External Resources¶

For further information consult authority guidelines at the Which?.