plipconfig

plipconfig [interface]
plipconfig [interface] [irq irq] [base address] [full] [fast] [nibble] [trigger] [auto] [mode mode] [noprobe]
plipconfig -V

interface
    The name of the PLIP network device to configure (e.g., plip0, plip1).

irq irq
    Sets the Interrupt Request (IRQ) line used by the parallel port. Common IRQs are 7 and 5.

base address
    Specifies the I/O base address of the parallel port hardware (e.g., 0x378, 0x278, 0x3BC).

full
    Enables full-duplex operation for bidirectional data transfer.

fast
    Activates the fast transfer mode, often using EPP/ECP (Enhanced Parallel Port/Extended Capabilities Port) if supported by the hardware and driver.

nibble
    Configures the device to use nibble mode, a slower 4-bit data transfer method.

trigger
    Sets the parallel port to trigger mode, using the strobe line for data transfer control.

auto
    Allows the driver to automatically negotiate the best transfer mode.

mode mode
    Sets a specific PLIP operating mode (0-3), with mode 0 typically being the fastest and mode 3 the slowest.

noprobe
    Prevents the command from probing for the parallel port hardware, useful if the hardware is known to exist but probing causes issues.

-V
    Displays the version information for the plipconfig utility.

The plipconfig command is a specialized Linux utility used for configuring parameters of the Parallel Line Internet Protocol (PLIP) network devices. PLIP is an older, hardware-based networking protocol that allows two computers to communicate directly over their parallel (printer) ports using a special null-modem cable. While largely superseded by modern networking technologies like Ethernet, USB, and Wi-Fi, plipconfig provided the means to set crucial operational parameters for these devices, such as the I/O base address of the parallel port, its interrupt request (IRQ) line, and various data transfer modes (e.g., full-duplex, fast, nibble). It was essential for establishing and troubleshooting these direct parallel port connections in early Linux environments. Today, its usage is primarily historical or for very specific legacy systems.

The plipconfig command and PLIP networking are largely obsolete in modern computing environments. Parallel ports are rarely found on new hardware, and more robust and faster networking options are universally available. Use of PLIP requires specific parallel port null-modem cables and kernel modules (like parport_pc and plip) to be loaded and configured. Modern Linux distributions may not include PLIP support by default in their kernels, or the necessary utilities might be absent. It offers no security features inherent in modern network protocols.

The Parallel Line Internet Protocol (PLIP) was a basic networking protocol that reused the existing parallel printer port hardware for network communication. It operated by bit-banging data over the parallel port's data and control lines, using a specialized 'null-modem' parallel cable to cross-connect the necessary pins between two computers. Due to the nature of parallel port hardware, PLIP connections were inherently slow, typically achieving speeds in the range of 10-20 KB/s, significantly less than early Ethernet (10 Mb/s).

The PLIP protocol and consequently the plipconfig utility emerged in the early days of Linux (and other Unix-like systems) as a simple and inexpensive way to network two computers directly, particularly in environments without Ethernet hardware. It was commonly used for file transfers or playing early network games between two machines. Its importance waned rapidly with the widespread adoption and cost reduction of Ethernet cards in the late 1990s and early 2000s, followed by USB and wireless technologies. Today, plipconfig remains primarily as a historical artifact or for maintaining very old, specialized systems.

ifconfig(8), ip(8), parport(4), modprobe(8)