Meinberg reference clocks can be used to build your own time server or to upgrade an existing system. All Meinberg GPS, WWVB, MSF, DCF77 and IRIG clocks with a serial or USB interface can also be used with NTP as a highly accurate hardware clock. They are all compatible with the NTP reference implementation, which includes Meinberg clock drivers supporting all our products on the most popular operating systems.

Overview: PC Clocks (PCI / USB)

PCI Express Radio Clocks

PCI Express is the latest implementation of the PCI bus, which is only software-compatible with other PCI bus specifications. The PCI Express hardware layout is totally different (it is not possible to install a PCI Express card in a PCI/PCI-X slot or vice-versa).

Meinberg offers PCIe timing devices for computer and network synchronization in both low-profile and regular sizes.

PCI/PCIX Radio Clocks

MEINBERG PCI/PCIX Computer Clocks will synchronize the system time of PCI/PCI-X computers and provide an Application Programming Interface (API) to read accurate and precise time from within your own application. 

Key Features

-PCI LOCAL BUS interface, 3.3V or 5V, 33MHz or 66MHz, PCI-X compatible

-Plug and play

-RS232 interface

-Buffered hardware clock

-Configurable time zone

-Driver software for all popular operating systems

USB Radio Clocks
Radio Clocks and Time Code Receiver for the Universal Serial Bus (USB)

A perfect alternative to synchronize computer systems when a PCI slot or serial port is not available. Meinberg USB radio clocks contain an internal antenna and are powered by the Universal Serial Bus, so no external power supply is required.

Key Features

-Powered by USB (no extra power supply required)

-Receiver status LEDs

-Buffered hardware clock

-Internal Antenna and External Antenna Input (Radio Clock models)

-Time Code signal input (TCR model)

-Plastic Case

-Three-year Warranty

More than: https://www.meinbergglobal.com/english/products/pc-clocks.htm