Customer Display

A customer-facing display shows the sale as it happens: the customer sees lines appear while you scan, and the total. Hyvä POS supports three kinds, from a two-line text display to a second iPad.

Star SCD222U (Free Tier)

A 2×20-character display for Star printers.

• Connects to: the host Star printer's USB-A peripheral port, not to the iPad. Works with Star counter printers such as the mC-Print series and the mPOP (printer and cash drawer in one chassis).
• How it communicates: the iPad sends display commands over the printer's existing connection (Bluetooth, USB-C or LAN); the printer firmware routes them to the display. No extra pairing, no own power or network.
• Shows: the running total while you scan, and a welcome message between sales.
• Setup: Settings → Printers → [your Star printer] → Customer Display (SCD222U). One Star printer hosts the display at a time.

Epson DM-D30 (Free Tier)

Epson's customer display for TM-series printers, same idea as the Star display.

• Connects to: the host Epson printer. The DM-D30-111 plugs into the printer's peripheral (UB) port; the DM-D30-101 mounts on the printer chassis itself. It fits the TM-m30III, the counter setup that also powers the iPad and drives the cash drawer over one cable.
• How it communicates: the iPad never talks to the display directly. Commands travel over whatever connection the printer already uses, and the printer passes them through.
• Shows: running total and welcome message, like the Star display.
• Setup: Settings → Printers → [your Epson printer] → Customer Display.

Paired iPad (PRO)

A second iPad faces the customer and mirrors the sale live.

• Connects to: the register iPad directly, over local peer-to-peer networking (MultipeerConnectivity). The two devices find each other on the local network; no server, no Magento round-trip, and it keeps working when the internet is down.
• How to pair: on the second iPad, open Hyvä POS and choose Display mode; it searches for a register running PRO. On the register, enable Broadcast cart to display. The pairing is authenticated against the register's terminal identity, which is why this display is part of PRO.
• Shows and does:
  • The cart, live, as lines are scanned.
  • At payment, a QR code the customer scans to reach their receipt page, where they download or email the receipt themselves.
  • An email prompt: the customer types their own address for an emailed receipt.
  • A newsletter opt-in under the email field (PRO): ticked by the customer themselves, applied only after the receipt email was sent. The checkbox only appears when the store can act on it.
  • Reward-point earnings on the completed sale.

What the Displays Show

The two-line VFDs run a small state machine driven by the register: a configurable welcome message when idle, the just-added item and running total while scanning, the total during checkout and payment, a thank-you, and a configurable "closed" message when the register is closed to customers. Both lines are limited to 20 characters (the hardware's grid) and the welcome/closed texts are settable per printer.

The paired iPad mirrors the sale through more phases: live cart, payment in progress, paid, email capture, receipt QR, and thank-you. What is sent to the display is limited to item names, quantities and prices, never SKUs, internal ids or customer emails. Refund lines display as negatives. The pairing is remembered, so both devices reconnect automatically after a restart, and the two iPads only need to share a network; no internet is involved in the link itself.

Further behaviour of the paired-iPad display:

• Closed register: when no register session is open, every display phase shows a "closed" screen.
• Lost connection: if the display loses its host it shows a "one moment please" screen instead of the pairing picker; the picker returns only after a deliberate unpair.
• The QR at payment needs receipt sync: the display offers the receipt QR when the sale has synced through PRO receipt sync; otherwise the customer gets the email option only.
• Reward points show at the end: on the completed-sale screen the customer sees the points the purchase earned.

Which One to Pick

A text display is cheap, robust and needs no maintenance. The paired iPad shows the full cart and lets the customer handle the receipt themselves.