Path: utzoo!utgpu!ugw.utcs.utoronto.ca!CUVMA!SWL-L
Date:	Wed, 31 Jan 90 17:00:26 EST
Reply-To: Walter Doerr <dg2kk@infodn.rmi.de>
Sender: Short Wave Listener's List <SWL-L%CUVMA.bitnet@ugw.utcs.utoronto.ca>
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From:	Walter Doerr <usc!snorkelwacker!ira.uka.de!smurf!infodn!dg2kk@BBN.COM>
Subject:      POCSAG protocol info
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To:	UofToronto LAN redistribution <SWL-L%UTORGPU.bitnet@ugw.utcs.utoronto.ca>
Message-ID: <90Feb1.074424est.58673@ugw.utcs.utoronto.ca>
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Approved: devnull@gpu.utcs.toronto.edu

I am looking for details on a protocol called POCSAG which is used to
send messages to paging receivers.

Things I would like to know:

- What type of modulation is used ((A)FSK, MSK, etc.)?
- What bitrate is used to transmit the messages?
- What is the format of a message sent out over radio?.
  (Ideally this would be some kind of hex-dump with a short description
  what each byte means.)
- Are the messages sent synchronously or with start/stopbits?
- How are the messages encoded (ASCII)?
- What kind of checksum is used (CRC, parity bits)?

Motorola and other manufacturers of paging receivers use this protocol,
so it must be fairly standard.

Thanks in advance!

-Walter