Getting started

Verifone P400 setup: cables, power and first boot

Set up a Verifone P400 or P400 Plus PIN pad: pick the right cable, attach it, connect power, power on and read the first boot screen.

Applies to
Verifone P400, P400 Plus
Last reviewed
Oct 27, 2026 by Abdul Rashid

Ask Allstar AI about this guide

Exact messages this covers

  • DOWNLOAD NEEDED

Check first

  • What does the P400 plug into: a POS PC over USB, a PoweredUSB port, an RS-232 serial port, a Verifone countertop terminal (V200c or VX 520), or the network over Ethernet?
  • Does your cable have a DC power jack? If so, you need the Verifone power pack.
  • Does your setup need Ethernet, Wi-Fi or Bluetooth? Those do not work when the P400 runs on 5 V USB power alone.
  • Was the unit programmed and key-injected for your processor before it shipped?

To set up a Verifone P400, attach the right cable to the 28-pin connector under the rear cover, connect the other end to your POS or network, plug in the Verifone power pack last if your cable uses one, and wait for the payment application to load. The box holds only the PIN pad, so the cable and power pack come separately.

This guide covers the P400 and P400 Plus. If Allstar programmed and injected your unit, it arrives ready for your processor; you only need to cable and power it.

Before you start

Which cable? Pick it by what the P400 plugs into (Verifone part numbers):

Host Cable Power
POS or PC, standard USB CBL282-038-XX-A/B 5 V from the USB port (reduced features, see below)
POS with a 12 V PoweredUSB port CBL282-033-01-B From the host. 12 V PoweredUSB only, not 24 V
RS-232 serial host CBL282-031-XX-A (DB-9 with DC jack) Verifone power pack
Ethernet network CBL282-006-01-B, CBL435-005-02-A or CBL435-044-01-C (junction box with RJ-45 and DC jack) Verifone power pack
Verifone V200c countertop CBL282-036-01-A (serial) or CBL282-038-xx-A / CBL435-002-01-A (USB) From the V200c
Verifone VX 520 countertop CBL282-036-01-A (serial, RS-232 port) From the VX 520 (limited); power pack for full features
  • Power pack: use only Verifone PWR435-001-01-A (US). A wrongly rated supply can damage the unit.
  • USB power alone (5 V, 500 mA): Ethernet, Wi-Fi and Bluetooth do not work, the screen and volume are dimmed, and the keypad backlight is off. Use a power pack or PoweredUSB if you need those.
  • Turn off or unplug the P400 before connecting or disconnecting any cable, or you risk memory corruption.

Steps

  1. Pick a flat indoor spot near the POS and an outlet, away from heat, sunlight, moisture, metal and electrical noise. Expected: no metal near the contactless area.
  2. Unpack, check the carton and the tamper-evident label, remove the wrap and screen film, and keep the carton. Expected: no damage. If the label or case looks damaged, do not use the unit.
  3. Choose the cable that matches your host from the table above. Expected: you have the right part number, plus the power pack if the cable has a DC jack.
  4. With nothing powered, lay the P400 face down on a soft surface, slide out the rear compartment cover, plug in the cable's 28-pin connector, replace the cover and tighten the captive screw. Expected: the cable is locked in. Any MSAM or microSD card for your program also goes in this compartment, gold contacts toward the unit.
  5. Connect the other end to the POS, PC, network or countertop terminal. Route all cables first, then plug the power pack into the wall or a surge protector last, if your cable uses one. Expected: the P400 starts when it gets power.
  6. If the screen stays dark, hold the green Enter key for about 3 seconds. Expected: it powers on. (Cancel held 3 seconds powers off; Enter held 10 seconds restarts.)
  7. Watch the first boot. Expected: the Verifone copyright screen, then your payment application's screen. If DOWNLOAD NEEDED appears, no application is loaded: stop and contact support.
  8. Fit the privacy shield or mount the P400 on a swivel stand, angled so PIN entry cannot be seen. Expected: keypad shielded. The standard shield is the PCI-approved one; the half-height shield is only for swivel stands.

If that did not work

  • Will not start or shows garbage: use the Verifone power pack rated for the unit, plug it into a dedicated outlet, and check every cable connection, including the power connector.
  • Blank screen: tap the screen; it may be in screen-saver mode. Then check all cables.
  • Keys do nothing: treat it as a start-up problem above. If one function key gives an unexpected result, that is set by the payment application.
  • Cards fail: try other cards. Swipe with the stripe facing the keypad. Insert chip cards contacts up and leave them in until the sale finishes. For tap, hold the card within about 4 cm of the contactless logo on the screen with nothing in between. Check that any MSAM card is fully seated.
  • Network features missing: if the P400 runs on USB power only, Ethernet and wireless are disabled by design. Add the power pack or use PoweredUSB.

Contact Allstar support with the model, serial number, payment application, processor and the exact message on screen. Allstar support: 888-403-7066 or support@allstarterminals.com, Monday to Friday, 9 AM to 5 PM Central.

Sources

Stop and contact support if

  • Tamper-evident label damaged, case opened, or any tamper or security message on screen: stop, do not reboot repeatedly, contact support.
  • DOWNLOAD NEEDED on screen: the payment application is not loaded. Do not try to load software yourself; contact support.
  • The P400 asks for a Supervisor or system password you do not have: stop and contact support.
  • You only have a non-Verifone power adapter: do not use it. Verifone says a wrongly rated supply can damage the unit.

Contact Allstar support with the model (P400 or P400 Plus), serial number, the cable part number in use, the POS or host it connects to, the payment application, processor and the exact message on screen.

Contact support about this

Notes

  • The installation guide is titled P400/P400 Plus but does not list Plus-specific differences. The only hint is that Bluetooth and Wi-Fi are unavailable on USB power, which implies wireless on some variants. Which units Allstar ships have Wi-Fi/BT is an owner question.
  • Wi-Fi, Ethernet IP settings and the POS link are set in the payment application or System Mode (password protected). The installation guide gives no configuration steps for them.
  • Verifone's Quick Start Guide says to hold a key for about 10 seconds to power on; the installation guide's Device Overview says Enter for 3 seconds powers on and 10 seconds restarts. This guide follows the installation guide.
  • The guide also lists a P400 Dual MSR variant (separate guide DOC435-012-EN). It is not covered here.
  • Media playback must be off and volume reduced when the P400 is powered from a VX 520's serial port, per Verifone. Setting the volume is done in System Mode.

Sources

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