PAGER-RX V1.01 POCSAG Decoder.. Copyright (c) 1997 by Jason Petty. *************************************************************************** Copyright: ---------- PAGER-RX may be freely distributed, provided that no charge may be made other than reasonable charges for reproduction(5 pounds Max) and that the author is not responible for any harmful consequences from using this software, even if they result from defects in it. ------------------ Table of Contents ---------------------------------- 1. Introduction 2. Requirements 3. File list 4. Getting started 5. Message format 6. The 'Address.lst' file 7. The 'Reject.lst' file 8. Menu options 9. Key short cuts 10. Command line options 11. Signal indicator 12. Memory 13. Interface schematics 14. Last words ----------------------------------------------------------------------- 1.Introduction: --------------- PAGER-RX can decode POCSAG paging signals at either 512 or 1200 baud rates. It can be used for off-air decoding of POCSAG signals with a scanner/radio, and it is also very useful for testing POCSAG paging systems. Main features: 1) Decoding of Alphanumeric and Numeric message data. 2) Hex dumping of raw POCSAG codewords. 3) All POCSAG codewords are given an even parity and BCH ECC error check. This means only clean messages are displayed. 4) There are 4 program modes which allow you to control how messages are displayed and logged. 5) Signal indicator. For more information on the POCSAG paging format, see: POCSAG.doc. 2.Requirements: --------------- 1) Amiga 1200. PAGER-RX will also work on slower Amigas but at 512 baud only. 2) POCSAG interface (see: Interface schematics). 3) Any scanner/radio which covers the VHF band. 3.File list: ----------- This disk should contain the following files: PAGER-RX - Pager program. PAGER-RX.doc - User documentation. POCSAG.doc - Frequency information, and an explanation of POCSAG by Brett Miller N7OLQ. Address.lst - List of pager address values, for logging. Reject.lst - List of reject pager address values. 4.Getting started: ------------------ To start decoding at 1200 baud, do the following: 1) With the computer switched off, connect the POCSAG interface to your AMIGA'S serial port. 2) Plug the earphone jack of the interface into your scanner/radio's earphone socket(with radio switched off). 3) Set your radio to the desired frequency (e.g. 153.3500 NFM). 4) Set your radio's volume to about a quarter or until the signal indicator(top right of title bar) begins to move. 5) Load workbench and place the PAGER-RX disk in any drive. Double click on the PAGER-RX icon and the program should load and begin decoding at 1200 baud. 5.Message format: ----------------- When you receive a POCSAG pager message it will look something like: Address Function number Message ------- --------------- ------- 160500 3 Please phone office ASAP... Address: All address values are 6 digits long and indicate to a pager (which has the same address) that the person should be paged. Function number: The function number lives in the address codeword and indicates to a pager that the following message data should be shown in either alphanumeric or numeric format. Function numbers are 0-3. Because the function number has a different meaning to different pagers, PAGER-RX defaults to showing all data as alphanumeric(ASCII text). This can be changed either by the FM0 to FM3 command line options, by menu options or with the function keys F1 to F4. You can see the current function mode settings at the top right of the title bar. This looks like: FUNC: AAAA If you changed function mode 3 so that all data for that function is shown as numeric data then the function modes would look like: FUNC: AAAN Message: Messages can be any length and can be in Alphanumeric (7 bit ASCII) or Numeric (4 bit BCD) format. When ASCII messages are received with control sequences, the control sequence value is shown in square brackets, rather than ignored. This enables you to use the full ASCII character set, while testing a paging system. When 4 bit BCD numeric messages are received the values above 9 are shown as follows: 0xA - Reserved.('R' is displayed) 0xB - 'U' (For Urgency) 0xC - ' ' (Blank Space) 0xD - '-' (Hyphen or Dash) 0xE - ')' (Close Bracket) 0xF - '(' (Open Bracket) 6.The 'Address.lst' file: ------------------------- This file can hold up to 150 address values which inform you that a particular sender has sent a message. A short beep is heard and the address value is highlighted. Entering address values: To edit the 'address.lst' file, use a text editor or word processor which can save in the standard ASCII format. Each address value must be at least one space apart and 6 digits long. This file is looked for in the current directory. 7.The 'Reject.lst' file: ------------------------ This file can hold up to 150 reject address values. These address values will be ignored and will not be displayed. This overrides the 'Address.lst' file. 8.Menu options: Disk Menu: ---------- Open Log File: After selecting this option, a file requester similar to the workbench file requester will appear. Simply type the new file name and press enter. All messages(depending on Mode) will then be saved. Output notes: PAGER-RX keeps file sizes down to a maximum of 80K per file. If a file reaches this maximum size then it is closed and a new file is opened. The new file has the same name as the previous one except it has an additional extension number. e.g. test.log becomes test.log1 then test.log2 etc. Maximum extended files after the first file is 999. Maximum file name length before extension number is 26 characters. Close Log File: Close log file previously opened with 'Open Log File' option. Sync Menu: ---------- Type new sync codeword: Type new sync codeword in hexadecimal format. This value will replace the last sync codeword, and will also replace the third sync codeword displayed by 'Select sync codeword from list' menu option (below). (see: POCSAG.doc for more information on the sync codeword) Select sync codeword from list: Select replacement sync codeword from list. Current selections are: 7CD215D8 (Default) 7CF21436 (Private Paging) DEA27065 (Dummy, Changeable) View current sync codeword: Display the current Magic number. Baud Menu: ---------- Change baud rate.(1200/512/300): The baud rate is displayed on the title bar. The 300 baud rate value is a dummy value and can be changed with the 'Replace 300 baud value' menu item or with the '-B' command line option. (The most commonly used baud rate is 1200) Replace '300' baud value: This option allows you to replace the default '300' baud rate (as selected by the above option) to any baud rate between 50 and 1200. Func Menu: ---------- Change func mode 0: Change func mode 1: Change func mode 2: Change func mode 3: For information on what these option do see: Message format - Function number. Misc. Menu: ---------- Change program mode: Change program to one of the following modes. The current mode is displayed on the title bar. Normal. View/log all messages, except for those whose address is found in the 'Reject.lst' file. If the address is found in the 'Address.lst' file, then a beep is heard and the address is highlighted. Message. Only view/log pager address if it is followed by a valid pager message. If the address is found in the 'Address.lst' file, then a beep is heard and the address is highlighted. Log. Only view/log message if it`s address is found in the 'Address.lst' file. This option makes PAGER-RX behave similar to a real POCSAG pager. Debug. View/log raw POCSAG codewords in batches of 16. Faulty codewords are highlighted. This is useful for testing signal input. Pause message output: Pause message output to screen/file. Select same option to resume. Reverse mark/space logic: Reverse the way up PAGER-RX reads individual data bits. Print Text: Send all pager messages to a printer. This will stop any file output. To resume file output select this option again. This option follows the workbench printer preferences. To change the preferences you should consult your workbench manual. Help: Gives a list of key short cuts. Quit: Exit PAGER-RX. 9.Key short cuts: ----------------- Space-Bar: Change program mode. B: Change baud rate(1200/512/300). C: Close log file. M: Reverse mark/space logic. N: Type new sync codeword in hex format. O: Open log file. P: Pause program. P to resume. R: Replace 300 baud for any baud between 50-1200. V: View current sync codeword. W: Select sync codeword from list. F1-F4: Change function modes to alpha/numeric. Q/Esc: Quit. 10.Command line options: ----------------------- Syntax: PAGER-RX [-B] [LDB] [PM] [FM0] [FM1] [FM2] [FM3] Options must be spaced, without the square brackets, and can be in any order. -B: Replace 300 baud rate as selected by the 'Change baud rate' menu item, for any baud rate between 50-1200. LDB: The program defaults to a 2K disk buffer, this option will expand it to 10K, and reduce disk activity. PM: Change the default program mode(Normal) to one of the following: mode ---- ------- Message 1 Log 2 Debug 3 e.g. to set LOG mode you put, PAGER-RX PM2 FM0-FM3: Change the default pager function mode settings from alphanumeric to numeric. See: 'Message format' for further. e.g. PAGER-RX FM0 FM2 11.Signal indicator -------------------- The signal indicator is located at the far right of the title bar and moves from side to side(like a metronome). This is useful for testing a new interface. 12.Memory: --------- PAGER-RX will use around 230K when run. PAGER-RX also monitors memory. If you log messages to the ram disk and the amount of free memory drops below 50K, then PAGER-RX will close the log file and a requester will appear. You should then exit PAGER-RX and copy the log file to a floppy. 13.Interface schematics ----------------------- This interface connects to the serial port and converts POCSAG audio signals to +/- 12v square wave signals. The square wave signal is then fed to the DSR pin of the serial port. The interface is also powered from the serial port, RTS(-12v) and DTR(+12v). D1 *----------*-->|-------*-------> RTS pin 4 | | | 2 |\ |4 *-->|---* | >-----||--------*-----|-\ D2 | | C1 | | \----------*-------|---|-------> DSR pin 6 0.1uF | 3 | / 6 | D3 | | | *--|+/ | *-|<--|---* AF in from | | |/ 7 | | | receiver. / | *-------------|-*--|<-*-----------> DTR pin 20 R1\ | R3 100K | D4 100K/ *------/\/\------* \ / | \ R2 | / 10K *--*---------*--------------------------> GND pin 7 | >----------------------------* Diodes: IC: 1N914 or LM741 1N4148 14.Last words: -------------- For comments/bug reports or new ideas for PAGER-RX, please write to: Jason Petty 32 Balder Road, Norton, Stockton-On-Tees, Cleveland, TS20 1BE. UK If you need a reply, please enclose an SAE.