HSCSD

HSCSD

    While we are using Mobile GPRS , there would be an [E] or a [G] indicating whether it is using EDGE (Enhanced Data rates for GSM Evolution) (2.5G) or GPRS (General Packet Radio Service)(2G) is used for data transfer . But very rarely do we see an [H]. [H] indicates HCSD

      HSCSD (High Speed Circuit Switched Data) enables data to be transferred more rapidly than the standard GSM (Circuit Switched Data) system by using multiple channels. The maximum number of timeslots that can be used is four, giving a maximum data transfer rate of 57.6 kbps (or 38.4 kbps on a GSM 900 network). HSCSD is more expensive to use than GPRS, because all four slots are used simultaneously - it does not transmit data in packets. Because of this, HSCSD is not as popular as GPRS and is being replaced by EDGE.

        So don't be perplexed if you see an  [H] displayed on your phone while using GPRS. For more details look in the links given below

http://en.wikipedia.org/wiki/General_Packet_Radio_Service

http://www.mobile-phones-uk.org.uk/gprs.htm

Precharging of DRAM's

After the data is being fetched from the memory,a command called precharge needs to be given.This will close the current memory row address that was being used and allowing a new row address to be activated for the next data fetch.From the DRAM point of view this command is known as RAS Precharge.The time taken between the precharge command and the next active command(Read or write Command) issued is known as RAS precharge time(Trp).This time will affects the speed performance of the DRAM.So lesser time might cause Greater speed performance.

Modes of Fiber

You may heard about single Mode fiber and Multi Mode fibers.Modes of a fiber doesn't means that the number of frequencies supported by the fiber but it actually defines how the wave distributed in space or orientation of data wave inside the Fiber.More clearly, a single mode fiber will transmit different frequency data waves in a path parallel to the axis.Multi-mode fiber's will be used for to transmit different frequency waves in different paths/spacial paths.Don't be confused with the Wavelength used for the data transmission, a wave with definite wavelength is being used as a carrier for the different frequency data packets.For example 1300 nm Optical carrier will contains multiple frequency data and also same frequency data would be oriented differently in multi-mode fiber.