VP-Digi – Configuration explained / help (English)

This configuration print is used as a fill-in digipeater:

Print config 5L:
Modem: AFSK Bell 202 1200 Bd 1200/2200 Hz
Callsign: LA5L-5
Destination: APNV01
TXDelay (ms): 200
TXTail (ms): 50
Quiet time (ms): 100
USB: default mode: KISS
UART1: 9600 baud, default mode: KISS
UART2: 9600 baud, default mode: KISS
DAC type: PWM
Flat audio input: no
Beacon 0: On, Iv: 15, Dl: 1, WIDE1-1, !5913.72N/00609.17E#VP-Digi W1 LA5L
Beacon 1: Off, Iv: 0, Dl: 0, no path,
Beacon 2: Off, Iv: 0, Dl: 0, no path,
Beacon 3: Off, Iv: 0, Dl: 0, no path,
Beacon 4: Off, Iv: 0, Dl: 0, no path,
Beacon 5: Off, Iv: 0, Dl: 0, no path,
Beacon 6: Off, Iv: 0, Dl: 0, no path,
Beacon 7: Off, Iv: 0, Dl: 0, no path,
Digipeater: On
Alias WIDE: On, max: 1, rep: 1, traced, viscous-delay, unfiltered
Alias : Off, max: 0, rep: 0, untraced, unfiltered
Alias : Off, max: 0, rep: 0, untraced, unfiltered
Alias : Off, max: 0, rep: 0, untraced, unfiltered
Alias -0: Off, untraced, unfiltered
Alias -0: Off, untraced, unfiltered
Alias -0: Off, untraced, unfiltered
Alias -0: Off, untraced, unfiltered
Anti-duplicate buffer hold time (s): 90
Callsign filter type: blacklist
Callsign filter list: 0 entries
KISS monitor: Off
Allow non-APRS frames: Off
FX.25 protocol: Off
FX.25 TX: Off

📄 VP-Digi Configuration – Print config 5L

This document describes the configuration of VP-Digi used as a TNC and digipeater with callsign LA5L-5. It is set up as a fill-in digipeater, with one active beacon and using standard AFSK modulation for APRS.

🎛️ Modem and Audio Settings

Field	Value	Explanation
Modem	AFSK Bell 202 1200 Bd 1200/2200 Hz	Standard APRS audio modem, 1200 baud. AFSK modulation with 1200 Hz (mark) and 2200 Hz (space).
TXDelay	200 ms	Delay before transmitting after PTT is enabled – allows radio carrier to stabilize.
TXTail	50 ms	Time PTT remains active after the last bit is sent – prevents clipping.
Quiet time	100 ms	Minimum quiet time before sending is allowed (for carrier detect).
DAC type	PWM	Audio signal is generated using PWM (pulse width modulation).
Flat audio input	No	Indicates normal (non-flat) audio input processing.

🔌 Interfaces and Communication Ports

Field	Value	Explanation
USB	default mode: KISS	USB port acts as a KISS-TNC for a PC or controller.
UART1 / UART2	9600 baud, default mode: KISS	Both serial ports run in KISS mode at 9600 baud – usable with microcontrollers or radios.

📡 Callsign and APRS Message

Field	Value	Explanation
Callsign	LA5L-5	Identifies the digipeater in the APRS network.
Destination	APNV01	Identifies the software – APNV01 is for VP-Digi.

🛰️ Beacons

Beacon	Status	Interval	Delay	Path	Comment
0	On	15 min	1 min	WIDE1-1	Sends a position beacon every 15 minutes, with a one-minute startup delay.
1–7	Off	0	0	None	Not used. Only beacon 0 is active.

Beacon message:
!5913.72N/00609.17E#VP-Digi W1 LA5L
APRS format for fixed position with comment «VP-Digi W1 LA5L».

🔁 Digipeater Function

Field	Value	Explanation
Digipeater	On	The digipeater is enabled and forwards packets based on alias settings.

➕ Alias Configuration

Alias WIDE:

Parameter	Explanation
`max: 1`	Accepts only `WIDE1-N` paths (not `WIDE2-N` or above).
`rep: 1`	Forwards one time (e.g., `WIDE1-1` → `WIDE1*`).
`traced`	Adds `LA5L-5*` to the packet path.
`viscous-delay`	Adds random short delay to avoid collisions with other digipeaters.
`unfiltered`	No additional filtering – all matching packets are handled.

Other aliases:
All other alias lines are disabled to ensure only WIDE1-1 packets are digipeated. This is standard for a fill-in digipeater.

🛡️ Filtering and Duplicate Control

Field	Value	Explanation
Anti-duplicate buffer hold time	90 seconds	Prevents re-transmitting the same packet within this time frame.
Callsign filter type	blacklist	Excludes callsigns on the list (currently none).
Callsign filter list	0 entries	No blocked callsigns.

🛠️ Advanced Features

Field	Value	Explanation
KISS monitor	Off	Does not log or monitor all frames.
Allow non-APRS frames	Off	Ignores non-APRS data frames.
FX.25 protocol	Off	Optional future support for error-correcting APRS (FX.25).
FX.25 TX	Off	FX.25 transmission is disabled.

📌 Summary

VP-Digi is configured as a simple and effective fill-in digipeater:

Sends a position beacon every 15 minutes with WIDE1-1
Forwards only WIDE1-1 packets from mobile or low-tier APRS stations
Uses delay to avoid collisions with nearby digipeaters
Fully compatible with APRS standards

LA8DKA