A hundred people can use the phone off one optical cable. Optical cabling can be used for telephone wires and broadband. Optical cabling transfer speed is 10 GB/s (gigabytes per second). At this speed you could transfer a Blu-ray movie less than 30 seconds. There are two types of twisted pair cables. One is UTP (Unshielded twisted pair) and STP (Shielded twisted pair). UTP and STP were invented in the 1980’s because of the change of phone technology. These days’ people still use these cables because they are cheaper than optical and coaxial cables. UTP contains eight cables and they come in coloured pairs.
Backing storage: The memory with a computer system as a standard is relatively small and most of this is lost when the computer is powered off. To prevent this there are more permanent store for data this may include software, a secondary storage device or a backing store may be needed, you can also use the cloud to back up your data online. For a portable store for your data offline storage device are needed. •CD-ROMS •DVDS •Memory sticks •Floppy disks There are a lot of ways of backing store now that is on the market for a PC user, magnetic and optical and pen drive and flash memory cards.
Magnetic storage uses different patterns of magnetisation on a magnetically coated surface to store information in a non-volatile form. This data back be accessed using one or more read/write heads. Magnetic disks can also be available in external hard drives or internal hard drivers. External can be used for offline storage internal can be used for online storage. Optical devices have tiny pits etched on the surface of a disk to store data in a non-volatile form this can be accessed by a using a CD drive using a laser diode and observing the reflection.