Hi, I have an access control on my wife’s studio, I recently deployed asterisk/freepbx (SNG7-PBX16-64bit-2306), and I wonder if there is a gateway that I could use for example to dial *44 on the extensions and it will connect to the RF gateway, and this RF gateway should know how to communicate with 433.92 MHZ devices (this is normally used for remote controls, garage doors openers, gate openers, etc). I have been searching on the internet and I Can’t find something that would make this possible, I don’t mind having to code an interface in AGI.
Specifying the frequency is not enough. You also need to consider the modulation. You can probably get add-ons for Raspberry Pi that will handle at least some 433.92 Mhz devices, but I think it unlikely that there will be any telephony integration, so I think that will have to be done from first principles.
I did a double-take on the UHF frequency while recognizing it as an amateur radio frequency (also in a segment of the 420-450 band that is now shared with other services/devices in more recent years) – would this connection to an RF-gateway be intended for voice communications, or for controlling a remote device or devices? (For what it’s worth, DMR-gateways have since become somewhat common, as in the case of ‘AllStar,’ as one such example.)
Specifying the frequency is not enough. You also need to consider the modulation. You can probably get add-ons for Raspberry Pi that will handle at least some 433.92 Mhz devices, but I think you will need to provide custom code to link it to telephony.
That frequency is the nominal frequency used for, licence free, remote control and telemetry. The actual frequency band, at least in the UK, is 433.05 to 434.79, but the carrier frequency may not be well controlled and the receiver may be super-regen, so the centre of the band is used as the nominal frequency.
The same band is used, channelised, for analogue voice, generally referred to as LPD in walkie talkie specs. I think the OP is talking about telecommand use. That can be AM or FM, generally sending a digital pulse train, which can vary in format.
Voice could be phase/frequency or analogue, but would normally be the former.
Note that that band is somewhat overloaded in urban areas, and there other bands, with stricter duty cycle restrictions, that are less overloaded. Some are restricted to specific applications, e.g. social alarms.