--- name: "netrom" section: "4" platform: "linux" package: "ax25-tools" version: "0.0.10-rc5+git20230513+d3e6d4f-3" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/netrom" --- # netrom(4) NET/ROM amateur packet radio protocol family ## NAME AF\_NETROM - NET/ROM amateur packet radio protocol family ## DESCRIPTION **NET/ROM** is a protocol used extensively by radio amateurs. The Linux NET/ROM protocol family permits access to these protocols via the standard networking **socket** metaphor. The NET/ROM protocol layer only supports connected mode. IP traffic may be stacked on top of NET/ROM frames using a non-standard extension to the NET/ROM protocol. The only mode of operation is connected mode which is the mode used for a socket of type SOCK\_SEQPACKET (stream sockets are not available in NET/ROM). This requires that the user ensures output data is suitably packetised, and that input data is read a packet at a time into a buffer of suitable size. NET/ROM addresses consist of 6 ascii characters and a number called the SSID. These are encoded into a sockaddr\_ax25 structure which is provided to the relevant system calls. NET/ROM has some unusual properties. Notably in a multi-user system an AX.25 address is often associated with a user, and some users may not have such an association. a set of ioctl calls are provided to manage an association table. NET/ROM supports the following socket options for SOL\_NETROM. NETROM\_T1 is the T1 timer in 1/10ths of a second, NETROM\_T2 is the T2 timer in 1/10ths of a second. NETROM\_N2, the retry counter is also configurable. There is no 'infinite retry' option supported however. It is possible for an application to request that the NET/ROM layer return the NET/ROM header as well as the application data, this is done via the NETROM\_HDRINCL socket option. ## SEE ALSO [**call**(1)](/call/1.md), [**socket**(2)](/socket/2.md), **[setsockopt(2)](/setsockopt/2.md),** **[getsockopt(2)](/getsockopt/2.md),** [**nrbroadcast**(5)](/nrbroadcast/5.md), [**nrports**(5)](/nrports/5.md), [**netromd**(8)](/netromd/8.md), **noderest**(8), [**nodesave**(8)](/nodesave/8.md), [**nrparms**(8)](/nrparms/8.md). ## AUTHOR Jonathan Naylor G4KLX \