AFSK Paging Link
| Paging Modes | |
|---|---|
| AFSKAudio Frequency-Shift Keying Paging Link - POCSAG - Glenayre Paging Link - FLEX - ReFLEX - Golay Paging (GSC) - European Radio Message System (ERMES) - Multitone Paging |
 | |
|---|---|
| Frequencies | 72 MHz,850 MHz,928 MHz,76 MHz,450 MHz,460 MHz,470 MHz |
| Frequency Range | 72 MHz - 928 MHz |
| Mode | NFM |
| Modulation | AFSK |
| ACF | — |
| Emission Designator | — |
| Bandwidth | 9 kHz |
| Location | Worldwide |
| Short Description | A variant of POCSAG/FLEX that uses audio frequency shift keying (AFSK) based on Bell 202 standards. Typically found as uplinks/downlinks to pager network transmitters. |
| I/Q Raw Recording | Download file |
| Audio Sample | |
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POCSAG can be modulated in AFSKAudio Frequency-Shift Keying tones and transmitted over regular analog voice channels to send data without having to install expensive infrastructure upgrades. These variants use Bell 202-esque marks and spaces to modulate the signal.
The bandwidth of the original POCSAG signal determines how intense the modulation deviation is...
In the New England states: They use 1000 and 2300 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).. In the Midwest, the Bell 202 and a variant known as "1300-2100" also exist. 1300-2100 is for extremely low-bandwidth POCSAG... Phase inversion can also occur in some packets, which can produce a slight difference in sound...
Contents
Audio files:[edit]
I/Q:[edit]
https://drive.google.com/open?id=1weV6dasw3XuFUqomQhKPgW242Hk4Ma5q
Images:[edit]
Other examples:[edit]
Some other examples done with the Dutch POCSAG encoder part of SoRFMon's suite of demo software, and modulated with various Audacity plugins to create realistic waveforms:
The result when AFSKAudio Frequency-Shift Keying is mixed in with Flex @6400 BaudBaud (unit symbol Bd) is the unit for symbol rate or modulation rate in symbols per second.:
