| NTP servers (Network Time Protocol) are devices | | | | cable from this location preferably to the roof of |
| that can synchronise a computer network to an | | | | the building or by a window if you are using GPS. |
| authoritative UTC time source. UTC (Coordinated | | | | Locate an area to mount the GPS antenna, the |
| Universal Time) is a global time scale used | | | | ideal place would be the roof of the building with a |
| throughout the world and provided by atomic | | | | 180 degree view of the sky but bear in mind that |
| clocks. | | | | you will need to keep the GPS antenna close to |
| NTP servers can receive UTC time either across | | | | the power source on the roof of the building. |
| the Internet from places such as nist.gov or | | | | Things to avoid are air conditioning units and |
| windows.time. However, it must be noted that | | | | power distribution units as these will cause |
| Internet based timing references can't be | | | | electrical interference. |
| authenticated and may leave a network | | | | The cable should be run from the rackmount |
| vulnerable to malicious attacks such as DDoS | | | | enclosure to the selected mounting position leaving |
| (Distributed Denial of Service - normally caused by | | | | some slack cable in case you need to move the |
| malware that floods a server with traffic) that | | | | unit at a later date! Note: The maximum workable |
| blocks access. | | | | cable length for a GPS time server is 1000 |
| Fortunately dedicated NTP servers can receive an | | | | meters (1km). |
| authenticated timing reference through either the | | | | The four core cable is attached to the rear of |
| GPS network (Global Positioning system) or | | | | the rackmount NTP Time Server using a small |
| specialist long wave radio broadcasts normally | | | | junction box. The standard wiring for the GPS |
| emitted from a national physics laboratory. Some | | | | antenna is as follows: |
| NTP servers can receive both signals and even | | | | 1 - Brown, 2 - Orange, 3 - Yellow, 4 - Green, 5 - |
| use them at the same time to ensure better | | | | Blue, 6 - White |
| accuracy. | | | | With both units wired first power the GPS |
| GPS NTP servers are extremely easy to install as | | | | antenna then power up the rackmount server. |
| most time server manufacturers supply | | | | Some time servers gave a small LCD screen at |
| easy-to-use software with their devices. | | | | the front where on screen diagnostics are |
| Normally a GPS NTP server consists of a rack | | | | displayed. In most cases the unit will synchronise |
| mount NTP time server, A GPS receiver and IEC | | | | within 15 minutes, the delay is due to the GPS |
| Power Cables. | | | | antenna locating and synchronising to satellites. |
| For installation first locate a suitable area for the | | | | The configuration of the NTP Time Server can be |
| rack mount NTP Time Server in the rack mount | | | | achieved over the network using an internet |
| enclosure, bearing in mind you will need to run a | | | | browser. |