ugpibd

Userspace Rust daemon for USB-to-GPIB adapters that otherwise need an out-of-tree kernel driver. It exposes the bus over HiSLIP (IVI-6.1, port 4880) and VXI-11 (port 9010) so pyvisa and NI-VISA reach it with an ordinary TCPIP::...::INSTR resource string — with locking, clear, trigger, REN, SRQ, per-call timeouts and abort. VXI-11 is the highest-fidelity transport for mapping GPIB devices onto the network: every bus operation, including the client-driven read, is an explicit message on the wire. A Prologix-compatible port is available for older scripts, and the optional ugpibd-portmap package provides port-111 discovery for NI/Keysight VISA, cooperating with system rpcbind where present.

Supported adapters

Backend id	Adapter	USB id
agilent-82357b	Agilent/Keysight 82357B	0957:0518 → 0957:0718
agilent-82357a	Agilent 82357A	0957:0007 → 0957:0107
ni-usb-hs	NI GPIB-USB-HS	3923:709b
ni-usb-hs	NI GPIB-USB-HS+	3923:7618
ni-usb-hs	KUSB-488A	3923:725c
ni-usb-hs	MC-USB-488	3923:725d

The second USB id is what the adapter enumerates as once ugpibd has uploaded its firmware, which it does automatically. KUSB-488A and MC-USB-488 are untested, but take the same code path as the GPIB-USB-HS.

The adapter is picked with --backend; the default, auto, detects a single connected adapter by USB id.

Install

You get three binaries: the ugpibd daemon, the ugpibd-scpi client, and ugpibd-portmap (VXI-11 discovery on port 111 — shipped separately as the optional ugpibd-portmap apt package). The apt package also installs udev rules for adapter access, systemd units, and /etc/default/ugpibd.

macOS 12+ and Linux — Homebrew:

brew install berg/ugpibd/ugpibd

Debian 12+ / Ubuntu 22.04+ / 64-bit Raspberry Pi OS — apt:

sudo install -d /etc/apt/keyrings \
  && sudo curl -fsSLo /etc/apt/keyrings/ugpibd.asc \
       https://berg.github.io/ugpibd/apt/ugpibd-archive-keyring.asc \
  && echo "deb [signed-by=/etc/apt/keyrings/ugpibd.asc] https://berg.github.io/ugpibd/apt stable main" \
       | sudo tee /etc/apt/sources.list.d/ugpibd.list >/dev/null \
  && sudo apt update \
  && sudo apt install -y ugpibd

From source (Rust 1.75+):

cargo build --release
sudo cp contrib/60-ugpibd.rules /usr/lib/udev/rules.d/
sudo groupadd -f ugpibd && sudo usermod -aG ugpibd "$USER"
sudo udevadm control --reload-rules && sudo udevadm trigger

Then check the adapter is visible and start the daemon:

ugpibd --list
ugpibd

It binds 127.0.0.1 and serves HiSLIP (4880) and VXI-11 (9010). Use --bind 0.0.0.0 for remote access, --enable-prologix for the Prologix port, and RUST_LOG=ugpibd=debug for protocol tracing.

Connecting with VISA

import pyvisa
rm = pyvisa.ResourceManager("@py")
inst = rm.open_resource("TCPIP::localhost,9010::gpib0,15::INSTR")
print(inst.query("*IDN?"))

Resource-string syntax, where 15 is the instrument's GPIB primary address:

Transport	Resource string
VXI-11 (recommended)	TCPIP::<host>,9010::gpib0,15::INSTR
VXI-11, daemon's default PAD	TCPIP::<host>,9010::inst0::INSTR
VXI-11, the interface itself	TCPIP::<host>,9010::gpib0::INSTR
HiSLIP	TCPIP::<host>::hislip15::INSTR

VXI-11 is the recommended transport: it is the highest-fidelity mapping of GPIB onto the network, with every bus operation — including the client-driven read — an explicit message on the wire. Prefer the explicit ,9010 port form even though it matches the daemon's default: the string then works with no portmapper involved, on any port the daemon is configured for (--vxi11-port). Omitting the port (TCPIP::<host>::gpib0,15::INSTR) makes the client look the port up via the portmapper — see the ugpibd-portmap note below — and is the form NI and Keysight VISA produce on their own.

The HiSLIP sub-address may be written hislip<N>, gpib<N>, or bare <N>; hislip0 means the daemon's --default-address, as does VXI-11's inst0. Locking, service requests, and the rest of each protocol's semantics: docs/VXI11.md and docs/HISLIP.md.

VXI-11 details

Same instruments and same locking as HiSLIP (a lock taken over either protocol excludes the other), with the full protocol surface: client-driven reads, per-call timeouts, abort, SRQ events, and — via a bare gpib0 link — the interface itself (bus-wide clear, raw command bytes, bus status from the live control lines, unaddressed data transfer).

For clients that discover VXI-11 through the portmapper instead of a port in the resource string (NI and Keysight VISA) — Linux only, systemd:

sudo apt install ugpibd-portmap
sudo systemctl enable --now ugpibd-portmap

It registers with system rpcbind when one is running and serves port 111 itself when none is. Details and conformance notes: docs/VXI11.md.

ugpibd-scpi

A REPL bundled with the daemon, speaking any of its front-ends (--transport hislip|vxi11|prologix, default hislip).

ugpibd-scpi --addr 15                       # instrument at GPIB address 15
ugpibd-scpi --host bench-pi                 # no --addr: daemon's default PAD
ugpibd-scpi --transport vxi11 --addr 18     # e.g. for ++read, below
printf '++ren 1\n*RST\n*IDN?\n' | ugpibd-scpi --addr 15

A line the quote-aware hint calls a query (a ? outside string literals) is sent and its reply printed; any other line is written without reading. The address is fixed for the session.

Command	Action
++read	explicit addressed read (vxi11/prologix)
++clr	Selected Device Clear
++trg	GPIB trigger (GET)
++ren <0|1>	remote / local — semantics differ per transport, see ++help
++status	print the serial-poll status byte
++help	full reference, including per-transport caveats

Prologix

--enable-prologix adds a Prologix GPIB-USB-compatible ASCII server on port 1234 for scripts written against prologix-gpib-async or raw sockets. Supported ++ commands and their quirks: docs/PROLOGIX.md.

Capturing plots and prints

Instruments that plot or print to GPIB do not answer queries — they drive the bus at a listener, and until one exists they emit nothing at all. Two modes cover the two ways they do it, and which one an instrument needs is a property of the instrument, not a preference:

The instrument	Mode	Example
goes talk-only and drives the bus	++lon 1	HP 53310A, which prints PCL raster
addresses a plotter at a configured address	++dev <addr>	SRS SR620, which plots HP-GL to address 5

Both stream raw bytes to --capture-port, with no framing and no interpretation:

ugpibd --enable-prologix --capture-port 1235
printf '++mode 1\n++dev 5\n' | nc -q1 localhost 1234    # or ++lon 1
nc localhost 1235 > plot.hpgl                            # then press PLOT

--listen-only and --listen-address <addr> set the same modes at startup for a unit dedicated to capture; both are switchable at runtime, so a socket-activated daemon is never stuck in the wrong one.

Two things worth knowing before you debug a silent capture:

• Device mode gives up system control. No REN, no IFC, and the daemon is no longer controller-in-charge, so ordinary instrument traffic is refused until you leave the mode.
• A capture holds the bus. Other clients see up to one read timeout of added latency, and a capture client that stops reading stalls the talker — which on GPIB blocks every device, not just that transfer.

++lines dumps the eight bus control lines and is the first thing to reach for when nothing arrives: it distinguishes an instrument that is silent from one that is talking to somebody else. See docs/CAPTURE.md.

Running as a service (Linux)

The packaged ugpibd.service is deliberately not started or enabled on install — grabbing a USB device and opening a TCP port is not something a package should do behind your back. Pick whichever of these fits:

Goal	How
Run it once now	sudo systemctl start ugpibd
Start when an adapter is plugged in	set UGPIBD_AUTOSTART=yes in /etc/default/ugpibd
Start at boot regardless of hardware	sudo systemctl enable --now ugpibd

Daemon options go in UGPIBD_OPTS in /etc/default/ugpibd:

UGPIBD_OPTS="--bind 0.0.0.0 --enable-prologix --default-address 15"

Both settings take effect on the next start with no systemctl daemon-reload, because the file is read when the service starts rather than when the unit is loaded. /etc/default/ugpibd is a conffile, so your edits survive upgrades.

Autostart works by a udev rule pulling in ugpibd-hotplug.service, which checks UGPIBD_AUTOSTART and starts the daemon only if it is set to yes. When it is not set, that unit exits cleanly rather than failing, so nothing accumulates in systemctl --failed. Startup on plug also covers adapters already attached at boot, since udev re-emits their add events during early boot.

Multiple adapters

With one adapter attached, auto just works. When several are present, list them and pick one by its physical USB port:

$ ugpibd --list
#   backend          vid:pid    port           serial             product
0   agilent-82357b   0957:0718  1-1.1          (none)             82357B
1   agilent-82357b   0957:0718  1-1.2          (none)             82357B

$ ugpibd --usb-port 1-1.2

The port id identifies the physical socket, not the unit: on Linux the sysfs name (1-1.2), on macOS the IOKit location id (0x03440000). It is stable across replug into the same port and across firmware reload. One service instance drives one adapter, so put --usb-port in UGPIBD_OPTS.

If the kernel driver interferes (Linux)

If you see "failed to claim interface 0", the matching kernel GPIB driver has claimed the adapter: agilent_82357a for the 82357A/B, ni_usb_gpib for the NI adapters. These ship in the kernel (drivers/gpib, mainline since Linux 6.13) and in out-of-tree linux-gpib builds.

On Debian/Ubuntu, install the optional package:

sudo apt install ugpibd-blacklist-linux-gpib

Or do it by hand:

printf 'blacklist agilent_82357a\nblacklist ni_usb_gpib\n' \
    | sudo tee /etc/modprobe.d/ugpibd-blacklist-linux-gpib.conf
sudo modprobe -r agilent_82357a ni_usb_gpib

A deliberate modprobe still works either way, so this does not permanently lock you out of linux-gpib. Note that blacklisting ni_usb_gpib also disables the kernel driver for the NI GPIB-USB-B, which ugpibd does not support — module granularity is coarser than device granularity, so it cannot be exempted.

Origin and relationship to linux-gpib

The USB adapter backends in src/backend/ are not original protocol implementations. They were translated — re-expressed in Rust — from the in-kernel GPIB drivers under drivers/gpib/, as of the Linux v7.0 release (VERSION = 7, PATCHLEVEL = 0, SUBLEVEL = 0). That subsystem is the mainline home of the linux-gpib project by Frank Mori Hess. Concretely:

• agilent-82357a / agilent-82357b ← drivers/gpib/agilent_82357a/, plus the shared tms9914 controller logic
• ni-usb-hs ← drivers/gpib/ni_usb/ni_usb_gpib.c, plus nec7210 / tnt4882 register definitions

Important

Report bugs here — never to the linux-gpib or kernel drivers/gpib maintainers. ugpibd is an independent userspace re-implementation. Any defect you hit is a bug in this port: the upstream maintainers did not write this Rust code, cannot reproduce it, and cannot support it. Do not open issues, send email, or otherwise contact them about ugpibd. File it in this repository's issue tracker instead.

License

ugpibd as a whole is distributed under GPL-3.0-or-later; every source file carries an SPDX header.

• Translated adapter drivers (src/backend/) are a derivative work of the in-kernel drivers/gpib/ drivers (the linux-gpib project), copyright © 2001–2006 Frank Mori Hess and © 1997–2002 David A. Schleef, among others.
• HiSLIP message codec and protocol definitions (src/hislip/) are adapted from lxi-rs (GPL-3.0-or-later, © Gustav Palmqvist).
• Firmware blob (firmware/measat_releaseX1.8.hex) is proprietary Agilent/Keysight firmware, redistributed unmodified from fmhess/linux_gpib_firmware. It is not covered by this project's GPL; see firmware/LICENSE for its redistribution terms.