logging in or signing up Cellular Phones Siro Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINTLite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: Embed: Flash iPad Dynamic Copy Does not support media & animations Automatically changes to Flash or non-Flash embed WordPress Embed Customize Embed URL: Copy Thumbnail: Copy The presentation is successfully added In Your Favorites. Views: 8311 Category: Education License: All Rights Reserved Like it (5) Dislike it (0) Added: February 04, 2008 This Presentation is Public Favorites: 1 Presentation Description No description available. Comments Posting comment... By: dharmathakur (31 month(s) ago) i want to download this topic.please allow me to down load Saving..... Post Reply Close Saving..... Edit Comment Close By: dharmathakur (31 month(s) ago) i want to download this topic.please allow me to down load Saving..... Post Reply Close Saving..... Edit Comment Close By: dharmathakur (31 month(s) ago) thanks for the information Saving..... Post Reply Close Saving..... Edit Comment Close By: smourao (32 month(s) ago) I need down, Thanks for you presentation Saving..... Post Reply Close Saving..... Edit Comment Close By: KRW11 (32 month(s) ago) Thanks for posting - very useful Saving..... Post Reply Close Saving..... Edit Comment Close loading.... See all Premium member Presentation Transcript Cellular Phones : Cellular Phones SIT Conference 2005 Heartland Community CollegeItems of Interest: Items of Interest How Do Cell Phones Work Why Is It Called Cellular Cell Phone Identity Systems Digital Verse Analog Cell Phones What Happens When Your Cell Phone Places A Call How Does Roaming Work How A Telephone System Works How Cell Phones Work: How Cell Phones Work A cell phone is a radio like a walkie-talkie Walkie Talkie is simplex Only 40 channels to choose from 5 Watts can go about 4 miles Cell phone is Duplex There are around 1664 channels Has few milliWatts only limited rangeBlock Diagram of Cell Phone: Block Diagram of Cell Phone From Texas Instruments Web Site http://focus.ti.com/vf/docs/blockdiagram.tsp?family=vf&blockDiagramId=2007Why is it called Cellular?: Why is it called Cellular? An antenna tower handles calls from a short distance from it (Base Station) More antenna towers means more users can talk on cell phones Lower power the cell phone emits Repeat the frequencies used The antennas form small cells of coverage around the cityCell Sites Around A City: Cell Sites Around A CityCell Phone Identity Systems: Cell Phone Identity Systems Every cell phone has 2 unique identifications MIN – Mobile Identification Number A 10 digit telephone number 309-555-1212 ESN – Electronic Serial Number 32 bit binary number Built into the cell phoneSlide8: Inside of a Phone A Cell TowerDigital Verse Analog Systems: Digital Verse Analog Systems Older cell phones were analog Analog – AMPS, NMT Digital – GSM, PCS, CDMA The difference is between how your voice is transmitted between the phone and base station Cassette tape as analog CDs as Digital What Happens When Your Cell Phone Places a Call: What Happens When Your Cell Phone Places a Call Enter Phone # Scan Control Channels – finds closest base (determines which control signal is strongest) Sends Signal ¼ second MIN and ESN Number you want to call Base sends a Channel Assignment What frequency pair conversation will be on Connection The person you are calling is connected How Does Roaming Work: How Does Roaming Work Phone is on sends data message to cell site (MIN and ESN) Computer switches at phone company compare MIN of your phone to all of their customers MIN If you are a customer it gives you HLR (Home Location Register) If your are from another system, telephone system sends messages that you are on the system and creates a VLR (Visitor Location Register) How a Telephone System Works: How a Telephone System Works http://electronics.howstuffworks.com/telephone-image.htm You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.