pyjfl

An asynchronous Python client for JFL Active alarm panels: the frame codec and the TCP listener those panels dial in to.

Written for, and extracted from, the jfl_alarm Home Assistant integration — but it depends on nothing but the standard library and knows nothing about Home Assistant, so it is usable from any asyncio program.

pip install pyjfl

The topology is inverted

Nothing here dials a panel. The panel dials out, to the IP and port its installer programmed into its reporting destination. So this is a listener, and one listener serves many panels at once. A panel is identified by the serial in its 0x21 connection frame, never by its address: a panel that comes back on a new DHCP lease is the same panel.

import asyncio
from pyjfl import JflServer, PanelStatus

async def main() -> None:
    server = JflServer(host="0.0.0.0", port=9494)
    await server.async_start()

    link = server.link("0123456789")   # created on demand; outlives any one socket

    def on_packet(packet):
        if isinstance(packet, PanelStatus):
            print(packet.partitions, packet.zones)

    link.async_add_packet_listener(on_packet)

    while True:
        await asyncio.sleep(30)
        if link.connected:
            await link.async_request_status()   # the panel never pushes status

asyncio.run(main())

What it covers

Frames	Length-delimited reader that resynchronises rather than dying, checksum, sequence bytes
Status	Partitions, zones, PGM outputs, 32 trouble flags, the electric fence, mains and battery
Events	Contact ID classification, the panel's stored event buffer (0x48), 1073 records deep
Control	Arm / disarm / stay per partition, the electric fence, PGM outputs, zone bypass by bitmap
Programming	Reads the panel's whole configuration space (0x44): zone and partition names and types, users and their permissions, PGM functions, timers, holidays, schedules
Wireless	The radio inventory (0x59): detector model, firmware, signal quality, low battery

Every mapping in it was recovered from packet captures against real hardware and from JFL's own specification, and each is marked confirmed or located but unconfirmed in the source. Nothing is guessed: a wrong label on a read is still a confident falsehood.

Panels

Model byte	Panel	Partitions	Zones	PGMs	Fence
0xA0	Active 32 Duo	4	32	4	yes
0xA1	Active 20 Ultra / 20 GPRS	2	22	4	yes
0xA2	Active 8 Ultra	2	12	0	no
0xA3	Active 20 Ethernet	2	22	4	yes
0xA4	Active 100 Bus	16	99	16	yes
0xA5	Active 20 Bus	2	32	16	yes
0xA6	Active Full 32	4	32	16	no
0xA7	Active 20	2	32	4	yes
0xA8	Active 8W	2	32	4	yes
0x4B	M-300+	0	0	4	no
0x5D	M-300 Flex	0	0	2	no

Only the Active 32 Duo (firmware 7.60) has been validated against real hardware. The rest are implemented from the specification. An unknown model byte degrades to a permissive fallback and never raises.

⚠️ This controls a real alarm system

• Five wrong passwords lock remote access at the panel until someone performs a valid keypad operation. There is no retry loop anywhere near the 0x37 authenticated command family, and you must not add one.
• Prefer the unauthenticated command path (0x4E/0x4F); it carries no lockout risk.
• Never write to programming addresses without a full backup. A window write replaces bytes it never displayed — that is how JFL's own ActiveNet erased a user's access code during the capture session this library was decoded from.
• The programming space holds user access codes in clear. parse_users reads them far enough to answer has_code and discards them, so nothing downstream can leak what it was never given.

Credits

Author: Jonis Maurin Ceará. Based on the code developed by Carlos Jose Fernandes, https://github.com/fernac03/JFL_ACTIVE.

Licence

Apache-2.0. See LICENSE.

In short, and without being legal advice: you may use, study, share and modify this library freely, including commercially. If you distribute it, or anything derived from it, you must do so under the same licence, with the source available and the attribution above intact. Modifications you distribute have to be published — keeping an improved private fork to yourself and shipping it to others is exactly what this licence forbids.

Not affiliated with JFL

This is an independent, unofficial project by a private individual. It is not affiliated with, endorsed by, sponsored by or supported by JFL Equipamentos Eletrônicos Ltda., and carries no warranty of any kind. "JFL", "Active" and "ActiveNet" are trademarks of their respective owners and are used here only to identify the hardware this library talks to.

The protocol was recovered by observing traffic between the author's own panel and JFL's own software, for interoperability. It controls a real alarm system: read the warnings above before pointing it at one.