Federal Signal Modem-MSK
 | |
|---|---|
| Frequencies | 150 MHz,160 MHz |
| Frequency Range | 150 MHz - 160 MHz |
| Mode | NFM |
| Modulation | MSK |
| ACF | — |
| Emission Designator | — |
| Bandwidth | 6 kHz |
| Location | United States |
| Short Description | Signalling protocol developed for Federal Signal's various warning and mass notification appliances. This signal is used for activation and telemetry of all units in a network. |
| I/Q Raw Recording | Download file |
| Audio Sample | |
The Federal Signal Digital signalling protocol developed for Federal Signal's various warning and mass notification appliances. This signal is used for activation and telemetry of all units in a network.
The modem can be used in tandem with Federal Signal's Commander Digital System (aka SFCDware).
This protocol is commonly found among their line of mass warning and notification appliances. It is often heard over public safety/fire/police radio to control warning sirens. The entire system can be configured to transmit daily at a user-defined time to poll health checks on units in the system or manually commanded to activate or deactivate one or more nodes within a system. The protocol may also be used to remotely upgrade or program units if desired.
Specifications[edit]
- 2FSK Minimum Shift Keyed modulation
- Mark: 1200Hz
- Space: 1800Hz
- Baudrate: 1200 baudBaud (unit symbol Bd) is the unit for symbol rate or modulation rate in symbols per second.
- Error Correction: CRC16/XMODEM (poly 0x1021)
Hardware[edit]
For command and control, the Federal Signal SS2000+ encoder is typically used to interface with SFCDware and control various nodes within a system (be it Informer radios, FC controllers, or more). This device can be used standalone or attached to a PC running SFCDware for a graphical interface to a siren system. There is also a cut-down version called the Modem-MSKMinimum-Shift Keying (When Shift/Bd = 0.5. It is impossible to get this ratio to be lower than 0.5, hence it is called the 'Minimum' shift.) which will only work with a computer attached. This unit is also used in their mobile activation case (MAC-1/2)
Decoding Software[edit]
There is no publicly available software for interfacing with this protocol, though minimodem can output some data using the following command:
- minimodem --rx 1200 --mark 1200 --space 1800 -c 1.1 --sync-byte 0x555555 -q -f <file.wav>
The proper system software (SFCDware and/or Commander One) is only available to customers with an existing system to command and control. It's cost is above four figures.
Video Examples[edit]
