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GSM Dial-to-Open Gate and Garage Door Opener


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The C4 GSM Remote Control board is typically used for access control on external gates and garage doors.   A free call (the call is never answered) to the SIM card number from a registered telephone number will open your gates or garage doors.  There are no keyfobs or PIN numbers required giving ultimate flexibility as to who has access to your property.  The system has space for storing up to 512 numbers.

Programming is performed by SMS text using real word command like 'add' and 'remove' and can be done remotely at any time. There are no annoying passwords to remember as you are identified to the system by your mobile number.

The system incorporates a 7-day timer which allows the gate to be opened at a set time each day.  For each day there are up to 2 time periods where the gate is open i.e. Monday 8:00-9:00 and Monday 17:00-18:00.  The timer can be programmed remotely using a PC or by using SMS text messages.

By default the # relay is operated by calling the unit and the * relay is operated by SMS. Texting 'open' pulses the # relay and texting 'close' pulses the * relay.  These PCBs can be used for gates and shutters with both and open and close connections as well as controllers with just a single open/close input.

A complete list of accepted telephone numbers can be viewed via SMS text message. Additionally the memory can be scanned to find an individual number with the result displayed by an on-board LED and SMS text.

Balance checking is available using the FORWARD, SMS and DIAL commands (see manual).

The manual can be downloaded from here:

C4 Manual

Quick Start Guide available here:

C4 Quick Start Guide

Please note the board is supplied with a suitable antenna and 10cm SMA cable only.


The enclosure is available as an option.

Anything else I need to know?

All PCBs are supplied with a quad band stub antenna and a PCB to aerial connector cable (~15cm long). Anrtennas should be mounted outside of metallic enclosures. The PCB connector is a U.FL connector and the aerial connector is a standard GSM SMA connector shown below (should an extension cable be required).

SMA Conector for use with GSM Alarm Dialer

GSM products do not work on the 'Three' network as they are UMTS only.

Our optional sticky backed antenna makes installation quick and simple however this can only be mounted on non-metallic thin surfaces. Various antennas are available from our wesbite - please see 'Accessories'.


When deciding on which network to use we recommend that you search on the network provider home page to ensure you will receive a good signal in your geographic location. The Site Finder website is very useful for finding your closest mast and network

For indoor appplications the PCB fits into the Hammond 1591B enclosure.

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