go-ict

README

go-ict

Go drivers for ICT kiosk peripherals talking over an RS-232 serial port.

Sub-package	Device	Vendor page
l77	ICT L77 bill acceptor	https://www.ictgroup.com.tw/pro_cen.php?prod_id=16
sp1	ICT SP1 thermal receipt printer	https://www.ictgroup.com.tw/pro_cen.php?prod_id=124

Both devices are common in self-service kiosks, ticket vending machines, and bill-payment boxes. The drivers are pure Go on top of go.bug.st/serial, with no other third-party dependencies.

Install

go get github.com/ultramcu/go-ict

Requires Go 1.26 or newer.

L77 — bill acceptor

package main

import (
    "log"
    "time"

    "github.com/ultramcu/go-ict/l77"
)

func main() {
    dev, err := l77.New(
        "/dev/ttyUSB0",
        onEscrow,        // bill arrived in the escrow path
        onStack,         // bill stacked
        onReject,        // bill rejected
        onStatus,        // status / error frame
        l77.AutoHold,    // hold each bill until ReqBillAccept/Reject
        nil,             // optional log function (e.g. log.Printf)
    )
    if err != nil {
        log.Fatal(err)
    }
    defer dev.Close()

    go dev.Run()

    // Some devices need a moment after open before they'll accept
    // commands; the L77 reference app waits one second.
    time.Sleep(time.Second)
    dev.ReqReset()
    time.Sleep(time.Second)
    dev.ReqEnable()

    select {} // run forever
}

func onEscrow(d *l77.Device, b l77.BillType) {
    log.Printf("bill in escrow: %d THB", b.Value())
    if b.Value() >= 100 {
        d.ReqBillAccept()
    } else {
        d.ReqBillReject()
    }
}

func onStack(_ *l77.Device, b l77.BillType)  { log.Printf("stacked: %d", b.Value()) }
func onReject(_ *l77.Device, b l77.BillType) { log.Printf("rejected: %d", b.Value()) }
func onStatus(_ *l77.Device, s l77.Status)   { log.Printf("status: %s", s) }

The four escrow modes are:

Mode	Behaviour
l77.DoNothing	The escrow callback decides; you must call ReqBillAccept, ReqBillReject or ReqBillHold yourself.
l77.AutoAccept	Accept every bill that gets through the device's own validation.
l77.AutoReject	Reject every bill (useful for "out of service" mode).
l77.AutoHold	Hold the bill in escrow as soon as it arrives, then run the escrow callback so you can decide whether to accept or reject.

SP1 — thermal printer

package main

import (
    "log"

    "github.com/ultramcu/go-ict/sp1"
)

func main() {
    dev, err := sp1.New("/dev/ttyUSB1", 9600, nil)
    if err != nil {
        log.Fatal(err)
    }
    defer dev.Close()

    go dev.Run()
    dev.Init()

    dev.PrintfFormat(sp1.Large, sp1.Center, "Receipt #1234\n")
    dev.SetFontSize(sp1.Normal)
    dev.Printf("Item ............... 99.00 THB\n")
    dev.Printf("Tax ................. 7.00 THB\n")
    dev.PrintfFormat(sp1.Large, sp1.Right, "106.00\n")
    dev.LineFeed()
    dev.LineFeed()
    dev.SetQRCodeSize(5)
    dev.GenerateQRCode("https://example.com/receipt/1234")
    dev.LineFeed()
    dev.LineFeed()
    dev.LineFeed()
    dev.Execute() // CR -- commits the print job
}

Notes specific to the SP1's protocol:

• Print jobs are committed only when a CR (0x0D) byte is sent — call dev.Execute() at the end of every receipt.
• The printer needs a small idle period after a commit before it will accept the next batch reliably. The driver enforces this gap internally via a single drainer goroutine, so caller code can issue back-to-back Printf calls without sleeps.
• Font sizes are Small (~48 chars / line), Normal (~24), Large (~16). PrintfFormat software-aligns text inside the per-font budget so centred and right-aligned lines work at any size.

Serial port permissions

On Linux the user running the program needs read/write access to the serial device. Either add the user to the dialout group:

sudo usermod -aG dialout $USER

…then log out and back in, or chmod 666 the device for testing.

On macOS USB-serial adapters appear as /dev/cu.usbserial-…; no special permissions are usually needed.

License

MIT — SPDX-License-Identifier: MIT.