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Built-in Clients (Gateways)

javAPRSSrvr 4.0 and above supports internal clients such as APRSIGate. This can be any application, but the primary use foreseen is for it to be used as a gateway between RF or other service and APRS-IS. The interface used between javAPRSSrvr and the client is the same base class used for TCP connections. This interface is open to anyone who wishes to write a built-in client and provides the same flexibility available to remote clients.

Common Features

Directed Query Support

All bidirectional clients support directed ?APRST and ?PING? queries. Each client may support feature-specific directed queries like ?APRSM and ?APRSO.

Position Reports

Bidirectional clients can send posits. These posits can be fixed or tied to a GPS.

Status Reports

Bidirectional clients can send static status packets.


Bidirectional clients can support sending of telemetry. The telemetry can be generated via API or via a telemetry.txt file (similar to a wxnow.txt file). The telemetry.txt file solely consists of the data portion of the APRS telemetry packet (T#nnn,rest of packet) without terminator. The data field is parsed for internal storage (and validation) to be sent over the air.


APRSIGate has been written to this interface providing full gateway capabilities with a simplified TNC interface to make porting to different platforms simpler than in the past. Currently there are interfaces for AGWPE, the Linux kernel AX.25 modules, and direct connect to KISS TNCs in Windows, Linux, and other operating systems.


NSRDigi is a full featured AX.25 digi supporting the No-Source Routing algorithm. It is a non-APRS (resides in but does not communicate with) javAPRSSrvr client and shares the TNC interface with APRSIGate.

Object Generator

This internal client can create objects or items either via API (D-STAR repeater objects generated by DStarMonitor, for example) or via files (allows for dynamic object creation and deletion).

Weather Packet Generator

This client generates weather posit packets based on a wxnow.tx file. The format of a wxnow.txt file is:

Feb 23 2019 10:11
The first line is the local date and time generated in US locale format.
The second line is the data portion of weather posit packet including the 7 byte data extension at the beginning.
Note: The data porttion must conform entirely to the APRS101 spec to be properly parsed to use in an APRS packet.

Other Internal Clients

Other clients include WhoIsGate (callsign lookup), EmailGate (APRS email interface), and CQGate (CQ server). More information on using these can be found at the APRS-IS web site.

DBGate is a read-only client that populates a sysop supplied SQL database with packets and various packet type tables such as posit reports, tracking, etc. utilizes DBGate to maintain its tables.