Printers & the print agent: how restaurant KOT and bill printing works.

This series is for restaurant owners who want to understand Tadka Tech in depth. Each part follows one real story and stops at every button, and anything that doesn't click the first time is explained again with a second example.

Part 6 is printing: what the print agent is, how to install it, how to connect your thermal printer, how the KOT prints in the kitchen and the bill at the counter by themselves, how the cash drawer opens, and what to check when nothing prints.

This restaurant has put a new computer on its counter today and bought two thermal printers: one at the counter for customer bills, and one in the kitchen for KOTs. There's also a cash drawer, cabled into the counter printer.

The owner wants a slip to come out the moment a button is pressed, without a print dialog opening and without choosing a printer every time. This guide does that whole setup once, from start to finish.

The Tadka Tech portal runs on the internet, and your printer sits on your counter. A server on the internet can't reach your printer directly. And if the browser prints by itself, a print dialog opens every time and you have to pick the printer.

The print agent is a small, free program that runs quietly on that same computer. The portal hands it the slip and it sends the slip straight to the printer. It also sends the signal that opens the cash drawer.

The agent only listens to requests from inside that computer; nobody outside can reach it.

Keep four things ready. One: the counter computer, running Windows, Mac or Linux. Two: the printer already connected to that computer: powered on, paper roll loaded, USB cable in, and the driver that came with the printer installed, so its name shows in the computer's printer list. Three: the portal open in Chrome or Edge on that same computer. Four: an owner or manager login, because this is settings work.

One more thing: on an Android tablet, the kiosk or the kitchen TV, our apps handle their own printer and don't need this agent.

Open the left menu and go to Settings. Inside Settings there's a long list of tabs on the left; choose Receipt & Print.

At the top is the Receipt card, covered later. Below it is the Printers card, where all of today's work happens. The card is split into two steps: Step 1, install the print agent on this computer; Step 2, add your printers.

WhereSettings → Receipt & Print → Printers card

Step 1 has a big download button. The portal recognises which computer this is: this one is a Mac, so the button says Download for macOS. If your counter computer runs Windows, the same button says Download for Windows. For another computer, the other links are below it: Windows and Linux. The script bundle is only for technical people who have Python on their computer; you don't need it.

Below the button are short install steps for that computer. Press the button and a small file downloads; on slow internet it can take half a minute.

The same download is also in Settings, on the Apps & Downloads tab. All your apps are there, and the Print Agent card at the bottom has the same button.

WhereSettings → Receipt & Print → Printers → Step 1 (also Settings → Apps & Downloads)

In your Downloads folder you'll find the Tadka Print Agent Windows .exe file. If the browser asks whether to keep the file, choose Keep. Double-click the file.

The first time, Windows may show a blue screen saying Windows protected your PC. Don't worry: press More info, then Run anyway. A black window may flash for a moment and disappear; that's normal.

That's it: the agent is installed and running in the background. Windows asks this only the first time.

WhereDownloads folder → Tadka Print Agent .exe → double-click

On a Mac, open the downloaded zip file. Inside are two files; double-click the one called Install Tadka Print Agent.

If the Mac says it can't be opened, right-click that same file, choose Open, then Open again. On newer Macs, if Open doesn't appear on right-click, go to System Settings, Privacy & Security, and press Open Anyway at the bottom.

A Terminal window then opens and ends with Done: the agent is installed and running. Close that window.

WhereDownloads → zip → Install Tadka Print Agent

After installing, you never have to open the agent. It has no window and no icon. Every time the computer starts, the agent starts by itself, and if it stops for some reason it starts again on its own within a few minutes.

Install it only once per computer, on the computer you print from. When a new version comes out, just download it again and double-click; it removes the old one and takes its place. There's no need to delete the old file by hand.

Almost everyone will see this. After installing the agent, when you open Receipt & Print in the portal again, Chrome asks a small question at the top: this website wants to access other apps and services on this device. It means the portal wants to talk to your print agent. Press Allow.

If you pressed Block by mistake, printing won't work even though the agent is running. To fix it, click the small icon to the left of the website name in the address bar, turn on the Apps on device switch, and reload the page.

WhereChrome address bar → site icon → Apps on device

Now Step 2: adding printers. The Agent URL is localhost:8765, meaning the agent running on this same computer. Don't change it; the default is right.

Press Detect Printers next to it. The portal asks the agent which printers this computer has; the first time can take a few seconds. A message appears below: 3 printers found on this machine.

WhereSettings → Receipt & Print → Printers → Step 2 → Detect Printers

This list, Detected on this machine, shows every printer this computer knows about. POS80 Thermal is the counter printer. Kitchen KOT Printer is the kitchen one, connected by a network cable. Both have a green dot and say Idle, meaning ready.

The third, the office laser printer, has a red dot and says Offline. Red means the computer can't reach that printer: it's off, a cable is out, or the paper has run out. It's also a large-paper printer, not meant for slips, so it isn't added.

WherePrinters → Detected on this machine

Press + Add next to POS80 Thermal and its own card appears below. Press + Add next to the kitchen one too. Both are added, and the list now says Added next to them.

Each card has a name box at the top. Not everyone understands the machine name, so give it your own: Counter Printer, and Kitchen Printer for the other. Below, under Queue, the real machine name stays as it is.

WherePrinters → + Add → name box

Now the most important part: which printer prints what. Each card has three ticks: Prints KOT, Prints Receipt and Enabled. Both print ticks are on when a printer is added.

The counter printer doesn't need KOTs, so untick KOT; it now prints only the customer's bill. On the kitchen printer, untick Receipt; it now prints only KOTs.

Enabled: to switch a printer off for a few days without removing it, untick this.

WherePrinter card → Prints KOT / Prints Receipt / Enabled

Another example. A small café with a single printer: leave both ticks on, and it prints both the KOT and the bill. A bigger restaurant: KOT in the kitchen and the bill at the counter, as set up above.

If two printers have the same tick, the one higher in the list prints. So keep each job's tick on one printer only.

WherePrinter card → ticks

The bottom line of each card is about paper. Roll width: 80 mm or 58 mm. Choose the roll that's in the printer; it's written on the roll's box.

Then Cut: how the printer cuts the paper after a slip. Partial cut leaves it slightly attached; Full cut; or No cut for printers without a cutter.

Last is Characters per line, how many letters fit on one line. Leave it blank and it's 42 on 80 mm and 32 on 58 mm.

WherePrinter card → Paper / Cut / Characters per line

Here's why this matters. If the roll is 58 mm but the setting says 80, every line is longer than the roll, and each item's price breaks onto the next line. The bill looks scattered. Set the paper to 58 and everything fits on one line.

Even with the right paper, every printer prints a little differently. If prices still go onto the next line, lower Characters per line a little, for example from 42 to 40. If the slip looks stuck to one side with a lot of empty space on the right, raise it a little, for example to 48.

WherePrinter card → Paper / Characters per line

Now a test. Press the Test button on the counter printer's card. A message appears: test slip sent to Counter Printer.

The printer prints a slip like the one on screen. If you can read it, the printer, the agent and the paper width are all right. It also shows which width and how many characters per line are set. Run one test after adding every printer.

WherePrinter card → Test

Now the most important button: Save, at the top of the card. Press it and the message says Printer settings saved.

Don't forget it. If you add printers and set the ticks but don't press Save, everything is gone when the page closes, and nothing prints for orders.

WherePrinters card → Save

Below the printer list are three more settings. Auto-print KOT: turn it on and, as soon as an order is sent to the kitchen or a new item is added to an order, the KOT prints on the kitchen printer by itself, with no button to press. Auto-print bill: turn it on and the bill prints by itself as soon as payment is taken.

Both are your choice; keep them off and you print by hand each time. Receipt copies sets how many copies of the bill print for orders that come in from the website or QR, from one to five. Then press Save.

WhereSettings → Receipt & Print → below the printer list

Further down is another card, Auto Print Receipts, with Kiosk, Website and Table QR. Whichever you turn on, the bill for an order from there prints by itself at the counter as soon as the order arrives.

This applies only to orders that are already paid, and only on the computer where the receipt printer is set up. All of them are off by default.

The Kitchen Display card above it, for a small slip when an item is ready, is covered in the kitchen part of this series.

WhereSettings → Receipt & Print → Auto Print Receipts

Now the Receipt card at the top. Thank-you message: the line printed in the centre under the bill total. Footer text: the line below that, such as your GST number, FSSAI number or phone.

Receipt logo: the logo set here prints at the top of every bill, on thermal slips too. A logo on thermal paper needs a newer version of the agent, so keep the agent updated. After changes, press this card's Save.

WhereSettings → Receipt & Print → Receipt card

At the bottom is the Cash Drawer card. The drawer is connected to the printer, so the signal to open it also goes through the printer. Turn on Enable Drawer and an Open Drawer button appears at the top of the portal.

Under Printer, choose the printer the drawer cable is plugged into, here the counter one. Drawer pin: most drawers open on pin 2; if yours doesn't, try pin 5. Leave the pulse numbers as they are.

Press Test Connection: the agent shows online, with its version. Use Test Open Drawer to check that the drawer opens; a message with a green tick means the signal reached the printer. Then Save.

WhereSettings → Receipt & Print → Cash Drawer

A small check that will come in handy any time. Open a new browser tab and type localhost:8765/health in the address bar. This page comes straight from your agent.

ok true means the agent is running. version tells you which version is installed, and printers lists every printer on this computer. If the page won't open at all, the agent isn't running. When you talk to support, tell them this version number.

WhereNew browser tab → localhost:8765/health

Setup is done; now everyday use. Open the order for table T01: three items, no kitchen slip printed yet, and the KOT History on the right is empty. Press the chef's-hat button at the top, Print KOT.

No dialog opens and no printer has to be chosen. A message says KOT #1 sent to printer. Every item gets a KOT'd mark and the KOT History gets a line. The slip went to the kitchen printer, because only that one has the KOT tick.

The KOT shows the table, the waiter, the items and quantities. No prices, because the kitchen doesn't need them.

WhereOrder page → Print KOT (chef's-hat button)

Now the bill. Press the printer button at the top, Print Receipt. The message says Receipt sent to printer. This slip went to the counter printer.

At the top is the logo, then the token and table, each item with its price, GST and the total. Payment hasn't been taken yet, so Unpaid is printed in the middle. At the bottom are the thank-you line and footer from the Receipt card.

One order, two buttons, two different printers, with nothing to ask.

WhereOrder page → Print Receipt (printer button)

The drawer was enabled, so the Open Drawer button is now at the top of every page. When the cashier needs to give change, press it: a message with a green tick appears, meaning the agent sent the signal to the counter printer, and the drawer opens.

The drawer also opens by itself whenever a cash payment is taken. It does not open for card or UPI payments.

WhereTop of any page → Open Drawer

Now what happens if the agent is off. On this computer it has been stopped. Press Print KOT again. This time the portal doesn't leave you stuck: a box appears, Printer not connected. You can press Save as PDF to make a PDF of the slip, or print it on any printer.

If this box keeps appearing, the agent on this computer isn't running, or the browser is blocking it.

WhereOrder page → Print KOT → Printer not connected

The same thing in Settings: from the left menu open Settings, then the Receipt & Print tab, and press Detect Printers in the Printers card.

This time it says clearly: No response, start the print agent on this machine. The agent on this computer didn't answer. The next section lists what to check.

WhereSettings → Receipt & Print → Printers → Detect Printers

If nothing prints, check in this order. First: is the agent running? Open localhost:8765/health in a new tab. If the page doesn't open, double-click the downloaded file again, or restart the computer.

Second: if the page shows ok true but the portal still says No response, the browser is blocking it. Turn on Apps on device from the icon in the address bar.

Third: if the printer is red and Offline in Detect, check the printer's power, paper and cable, and print a test page from the computer's own printer settings. Fourth: check the printer's ticks, Enabled and Save once more.

Problems at install time. On Windows, antivirus sometimes blocks the new file, because it's new and few people have downloaded it, and printing suddenly stops. Open Windows Security; under Protection history you'll find Tadka Print Agent. Allow it, then download the file again and run it.

On a Mac, if the file won't open, use Open Anyway in Privacy & Security.

Put in a new computer? Install the agent on it too, detect and add the new printer, remove the old printer, and Save.

WhereWindows Security → Protection history

Problems with the slip. Prices going onto the next line: check the paper width and Characters per line. Logo not printing: the agent is old, so download the new one, double-click it, and check the version on the health page. Drawer not opening: is the right printer chosen? Try pin 5, and raise Pulse on from 25 to 50.

One important point: if the printer is off and you keep pressing print, the slips wait in a queue, and they all print together as soon as the printer comes on. So fix the printer first, then print.

The whole setup in five steps. One: download the agent from Receipt & Print. Two: double-click to install it, once per computer. Three: if Chrome asks, press Allow. Four: Detect Printers, Add, and tick each printer's job. Five: Test, and Save.

After that, your KOT prints in the kitchen, the bill at the counter, and the drawer opens with one button.