KISS mode

AXLoRaTNC implements standard KISS framing over USB serial (0xC0 FEND delimiters).

Switch to KISS

mode kiss

The mode is stored in NVS. To recover the console from KISS mode, type the plain text string console followed by Enter.

Protocol details

• KISS data frames (type 0) are treated as complete AX.25 frames from the host; AXLoRaTNC appends the FCS before LoRa transmit.
• Received AX.25 frames are FCS-checked and emitted as KISS data frames without FCS — exactly as a standard KISS TNC.
• KISS parameter frames (TxDelay=1, Persistence=2, SlotTime=3, FullDuplex=5) are accepted and drive the CSMA algorithm.

Compatible software

Application	Notes
kissattach (AX.25 for Linux)	Standard usage
Dire Wolf	Set ADEVICE to the ESP32 serial port
LinBPQ / BPQ32	See BPQ setup guide
F6FBB / LinFBB	Recommended via Linux AX.25; see FBB KISS guide
APRS clients	Any client supporting KISS TNCs

kissattach example (Linux)

sudo kissattach /dev/ttyUSB0 radio 44.137.x.x
sudo kissparms -c 1 -t 0 -s 10 -r 255 -p radio

Replace /dev/ttyUSB0 with the actual device path. Prefer /dev/serial/by-id/... for a stable name across reboots.

For connected-mode BBS traffic over LoRa, use PACLEN around 40-64 and MAXFRAME/window 1 on the host. If stats shows qdrops, the host is sending faster than the radio queue can drain.

Baud rate

Always 115 200 baud. The ESP32 USB CDC port auto-negotiates; the baud rate set on the host is ignored.