With a dial-up PSTN connection, we still use analog modulation techniques, the quality of which can vary greatly, depending on the line noise, distance and hardware quality, so it is possible that the worst case scenario can be even lower than 3 kb/s.

So in many worst case scenario calculations, 50% of the data transfer rate should be used.įor example, if we have a dial-up Internet connection with a typical modem of 56 kb/s, the maximum transfer rate will be around 6 to 7 kB/s, as the best, and around 3 kB/s as the worst case scenario. Therefore, when making a rough calculation as to how long it would take to download a file over a particular data link connection, the Mb/s data transfer rate needs first to be converted to MB/s by dividing it by 8 also, allowance should be made for traffic collision losses and noise, which could vary anywhere from 10 to 50%. In order to be able to understand and calculate this the readers should be reminded that there is a difference between bits (marked with the lower case “b”) and Bytes (marked with capital “B”). One of the most common questions in CCTV today is how quick an image update is over a network or how long a download of certain footage will take. This allows the network to expand to accommodate new devices without requiring any modification to those devices already on the network. Once a device attached to this cable, it had the ability to communicate with any other attached device. The original Ethernet described communication over a single cable shared by all devices on the network. The Ethernet standard has grown to encompass new technologies as computer networking has matured, but the mechanics of operation for every Ethernet network today stem from Metcalfe’s original design.

In the beginning coaxial cable was used for most Ethernet networks, but twisted pair, first Category 3, then Category 5 and Category 6 became the preferred medium for small LANs.Įthernet uses a bus or star topography (or mix of the two) and supports data transfer rates of 10, 100, 1000, or 10,000 Mb/s.

Vlado Damjanovski, in CCTV (Third Edition), 2014 Data speed and types of network cablingīy definition, Ethernet is a local area technology and works with networks that traditionally operate within a single building, connecting devices in close proximity.

Virtual wire library maximum data rate