Bringing A Legacy Pager Network Back To Life

[Jelmer] recently found his old pager in the middle of a move, and decided to fire it up to relive his fond memories of receiving a page. He soon discovered that the pager’s number was no longer active and the pager’s network was completely shut down. To bring his pager back to life, [Jelmer] built his own OpenWRT-based pager base station that emulates the POCSAG RF pager protocol.

[Jelmer] opened up his pager and started probing signals to determine what protocol the pager used. Soon he found the RF receiver and decoder IC which implements the POCSAG pager protocol. [Jelmer] began going through the sparse POCSAG documentation and assembled enough information to implement the protocol himself.

[Jelmer] used a HLK-RM04 WiFi router module for the brains of his build, which talks to an ATMega that controls a SI4432 RF transceiver. The router runs OpenWRT and generates POCSAG control signals that are transmitted by the SI4432 IC. [Jelmer] successfully used this setup to send control signals to several pagers he had on hand, and plans on using the setup to send customizable alerts in the future. [Jelmer] does note that operating this device may be illegal in many countries, so as always, check local frequency allocations and laws before tackling this project. Check out the video after the break where a pager is initialized by [Jelmer]’s transmitter.

24 thoughts on “Bringing A Legacy Pager Network Back To Life

  1. POCSAG is still around and used extensively in the public service industry. Many Hospitals,, EMS, fire and Police provides carry them with them. For a former eployer (Fire Department) I wrote an application which uses rtl_fm and a tweaked multimon to decode them, parse the details such as department being dispatched and details of the dispatch into a DB, and a web front-end to search and receive notifications on. It’s still pretty popular, and new pagers are being developed for it – just not for the private sector. I think some ham’s have been using it as well.

    1. > I think some ham’s have been using it as well.

      Yep, it’s perfectly legal for licensed amateur radio operators to use POCSAG paging over licensed frequencies, and I’ve considered testing it for automated Skywarn alerts.

      1. It may be legal but there are no commercial pagers sold that cover the amateur radio frequencies, so you’d have to come up with your own receiver. At that point that isn’t much reason to use POCSAG in the first place.

        1. Frequency change is easy so you don’t need to rework the whole receiver. A simple crystal change makes it work. Very cheap and there are companies that will do it for you. Lots of Amateur radio operators are doing it. There is even a group in the US linking there towers. I think Germany was another area were amateurs are using POCSAG as well if memory serves.

          1. This is very interesting news. I recently ran across a great deal of brand new pagers as well as programming equipment and software. I have probably 2000 pagers that vary from texting to the older simple models with just phone numbers to call. I was wondering what in the world I was going to do with all this stuff. It came as part of a package deal when purchasing the contents of an old Motorola dealership. If anyone’s interested, in any of these items, please post your request. My email is:
            I am going to check with our local ham club and see if they are interested in any for our sky warn system. 73’s!

  2. I still have my old pager. Ah, the memories… I have no use for it whatsoever but I can’t bear to part with it so it has come along for way too many moves and still sits in one of my parts bins in my garage.

    Now this has me thinking about actually finding a use for it. Hmm… what would I have it display?

  3. remember pagers very well. used to make the things at philips factory in cambridge uk. we did 2 12 hours shifts 7 days a week. turned out around 500 pagers per shift.never actually owned one. this was in 1996 or so.

  4. I’m surprised pagers didn’t make a comeback after the wikipedia and snowden thing, yes it can be read by anybody, but you can’t be pinpointed, and can use your own coded messages like the drugs dealers used to do.

    1. LOL! what did wikipedia ever do to you? I think you meant wikileaks. Someone creative that wants to remain “off the radar” could send false GPS data to their phone. That way they can only trace you to the tower. So far as encrypted messaging that is pretty simple on an Android phone.

      1. Ha, yes indeed, I mean wikileaks, although a lot of the snowden and wikileaks stuff did make it to wikipedia entries so I have that going for me.
        And as for the tracking, those towers are more precise than you think, plus as you hop from tower to tower they can nicely determine your direction/destination too.

  5. We were thinking of developing a local pager network for a game we wanted to create at our Doctor Who store here in Indianapolis, Indiana. The game would be a “live action” roleplaying type adventure and you would receive hints through a local paging network (the pager would be given to a member of the team and he would receive text-message hints as he moved through the game). The setup would be something like, “The Doctor has been trapped in time and space, and he can only communicate with you through this pager…” and off the adventure would go. This is a great idea you have here.

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