POCSAG

POCSAG Quick Start Guide

POCSAG is a one-way pager protocol that is carried by DAPNET (Decentralized Amateur Paging Network) which was developed by German Amateurs. You can configure your Pi-Star hotspot to transmit these messages on the worldwide POCSAG frequency of 439.9875 MHz (or any other frequency you choose). See the DAPNET wiki for a basic overview of POCSAG. POCSAG is an acronym for Post Office Code Standardization Advisory Group which developed the code for the British Post Office.

Your hotspot will transmit POCSAG messages on a POCSAG frequency then change back to your regular hotspot frequency. If the hotspot is busy with another mode POCSAG messages will be stored until the other mode’s hang time ends and then the stored messages will be transmitted.

To get your hotspot ready to transmit POCSAG you start with a request for a new DAPNET Account: Open a support ticket and request a new account with RIC (pager ID) at: https://support.hampager.de/index.php The RIC code (capcode) will be your pager “address”, similar to your DMR ID.

Sign in with the new DAPNET account then open another support ticket and request a new transmitter. You will receive an email with your transmitter’s node callsign (usually your call sign) and a transmitter authorisation key.

Pi-Star Hotspot Upgrade

  • Must upgrade MMDVM modem to 1.4.0 or later
  • Must upgrade to Pi-Star 3.4.16 or later

Pi-Star POCSAG Setup

On main Configuration page enable POCSAG mode and click “Apply Changes”.

Main Configuration

Enable POCSAG mode in “MMDVMHost Configuration”, click “Apply Changes”, fill in the “POCSAG Configuration” section near the bottom of the page and click “Apply Changes” again.

Then set the  POCSAG Configuration (near bottom of page)

Node Callsign POCSAG: what you registered it as, usually your callsign

Radio Frequency POCSAG: 439.987.500 (worldwide)

DAPNET AuthKey: Your transmitter’s authorization key assigned by DAPNET

Click “Apply Changes”

The latest POCSAG activity will show on the Pi-Star dashboard. POCSAG activity can also be seen on the “Live Logs” page.

We can use the Android DAPNET app to send messages. DAPNET limits the page to 80 characters.

We can send POCSAG messages by using a DMR SMS message. Send an SMS message to Private DMR Contact 262994 in this format:

M1ABC This is a Test Message

We can use the Pi-Star SSH command line to send POCSAG messages:

You must put your DAPNET website (hampager.de) user name and password in the DAPNET API section found at Configuration/Expert/DAPNET API. Enter your TXAREA, for the UK use: uk-all. Click “Apply Changes”.

USER and PASS are your hampager.de login credentials (not your transmitter callsign and Authkey). TXAREA for the UK is “uk-all”.

Then issue this command (with your target callsign and message) at the SSH Access command line:

sudo pistar-dapnetapi M1ABC “This is a test message, please ignore it”

To get to the SSH Access command line select Configuration/Expert/SSH Access and sign in.

We can view actual POCSAG message contents in the Pi-Star log. Click on Pi-Star’s “Configuration/Expert/SSH Access”, log in, then enter “tail -f /var/log/pi-star/D*” to view all real-time POCSAG activity including message text.

POCSAG Pagers

We can use a pager to receive POCSAG pages but the pager must be POCSAG capable (most are) and programmable to use 439.9875 MHz. You must also set your capcode (Channel Access Protocol code) or RIC (Receiver Identification Code) which functions as the pager ID. Pager sellers use the term “capcode” for the pager ID and may not understand the term RIC (capcode = RIC). DAPNET POCSAG messages are 1200 baud.

I purchased a new Chinese GP2009N pager on ebay for US$95 delivered with 3-day shipping (yes, 3-day shipping from China to the East Coast USA). It an Alphapoc 602R X4 clone. Just tell the seller, witoptech, the POCSAG frequency and your capcode (RIC) and she will pre-program it for you and all you’ll have to do is add an AAA battery and you’re good to go. The pager is hand programmable for RIC, freq and baud. I’m very happy with the pager. Here’s the GP2009N User Manual and the GP2009N Programming Software which allows you to set the frequency and up to eight RIC codes.

This is the Chinese GP2009N pager I use. Buttons are Up, Down, Function

This is the GP2009W watch version.

Hand Programming the Alphapoc 602R, GP2009N and Ganray Pagers

1. Turn pager on

2. Hold the Up and Read buttons down for about 3 seconds until the password is shown.

3. The default password is 0000, press the Down key (2nd from top) to move right until the RIC (capcode) page is shown.

4. Press the Function key (third from top) to change [OFF] to [ON]

5. Press the Down key to move through the characters, press the Function key to change the values.

6. As you continue to the end of the RIC page you’ll move on to the next page with BAUDRATE: 1200, POLARITY: NORMAL, FREQ: xxx.xxxx M and PROGRAM EXIT

7. Change the frequency by using the Down key to move between characters and use the Function key to change the numbers.

8. Move to PROGRAM and hit the Function key to save the changes.

9. If you do not want to save the changes move to EXIT and hit the Function key.

Pagers Confirmed to Work With DAPNET

The following pagers have been confirmed to work on the Amateur POCSAG system and worldwide frequency. Most have several models that cover different frequency ranges. You must verify with the seller that the pager can operate in the 70cm Ham band. Be aware that some pagers can only do FLEX protocol and will not receive POCSAG:

Apollo AL-A29 – Must verify the frequency range overlaps the Ham UHF band (most don’t).

Apollo 924 UHF 430-450 MHz

Alphapoc 601, 602R X4 – frequency and RIC can be hand programmed (see above), proprietary USB cable is required to program via free software

Ganray (Chinese AlphaPoc 602 clone) – frequency and RIC can be hand programmed (see above), proprietary USB cable is required to program via free software

GP2009N pager and GP2009W wristwatch – frequency and RIC can be hand programmed (see above), proprietary USB cable is required to program via free software

Daviscomms BR800, BR802 – verify it can be set to Ham band, most cannot

NEC 21/A Skyper – not hand programmable

Apollo ALA25 T60 (Gold) R8 GP – lowest usable frequency is around 442 MHz so no good for the 439MHz POCSAG frequency

Many used commercial pagers can be used for Amateur POCSAG but be careful when purchasing. Verify it is compatible with POCSAG protocol (not just FLEX) and the frequency, Baud and capcode can be set before you spend your money. Many old pagers cannot do 449 MHz. Some allow the frequency and capcode (RIC) to be set by hand, others require a programming cable and software. Many sellers will set the frequency and capcode for you.

It has been reported the Alphapoc 602, GP2009N, GP2009W and Ganray pagers use the same programming cable and software.


Source: Rob Robinette K9OJ