1978 Bell Labs video on the introduction of the "modern" cellular system - Page 1
Forum section: electronics / general

author: Stonent
author_rank: Super Contributor
timestamp: April 25, 2015, 01:22:14 am
content: I found this video from the AT&T Bell Labs Archives quite interesting. It explains the history of wireless phone technologies (half duplex phone calls!) and the concepts behind cellular technology which in many ways are still used today even though the analog system is long gone.Also note the 666 channel limit which I'm sure proves cell phones are evil.

author: Noise Floor
author_rank: Regular Contributor
timestamp: April 25, 2015, 02:48:12 am
content: Interesting.This video made me think of how Google will decide what video's to preserve over the years vs let die. I mean this has real historical value, but all the millions of cat videos can't be worthwhile for them to store forever. How will they filter when the time comes?

author: justanothercanuck
author_rank: Frequent Contributor
timestamp: April 25, 2015, 03:56:49 am
content: I love these old videos. We've come a long way since the old mechanical systems driving POTS.

author: German_EE
author_rank: Super Contributor
timestamp: April 25, 2015, 09:07:22 am
content: Something I have always wondered, suppose my friend calls my mobile phone from his landline, how does the cellular network know how to direct the call to my nearest base station? There are thousands of base stations and millions of handsets which means a big database somewhere.

author: SeanB
author_rank: Super Contributor
timestamp: April 25, 2015, 09:24:04 am
content: Distributed database, the local cell knows which handsets it has had recent contact with and where it has not handed them off to another base station ( it polls those units that are not active every few minutes which is that common chirp you get from a phone near sensitive electronics when you do not have a data channel active) so it reports this to a local master database. the incoming call results in a lookup for location, starting first in the local cells then moving out to cells further out in the network ( making use of the fact that you typically call a phone near your location or the gateway into the local part of the cell network) then finally using a database of phones that are known to be roaming off the network. If no result then it will either go to voicemail ( if set up) or the subscriber unavailable message.Typically the far databases will take too long to respond to the request, but will return a reply if it is available, which is cached. Thus if you try again within a short time the call will go through.

author: Red Squirrel
author_rank: Super Contributor
timestamp: April 25, 2015, 10:07:06 am
content: AT&T archives has some pretty cool videos, like phone switching and stuff. What's interesting is a lot of the 70's tech is still in use today like DMS. Harder to get parts for but there are companies that make them.

author: SeanB
author_rank: Super Contributor
timestamp: April 25, 2015, 10:56:17 am
content: Good is well is the weekly security analysis in Threattraq, which is always worth watching. Interesting things to do with internet security, and currently the thing coming out is SSL is really good to implement.

author: Psi
author_rank: Super Contributor
timestamp: April 25, 2015, 12:11:35 pm
content: Quote from: Noise Floor on April 25, 2015, 02:48:12 amThe time will never come, more storage will just keep being available.I could fit all the computer software that existed 20 years ago on my 2TB disk.

author: SeanB
author_rank: Super Contributor
timestamp: April 25, 2015, 12:37:59 pm
content: When they start to get to close to 70 to the 11th power videos. 1.98E20 videos will be close to the limit as to the number of videos you can reference with a unique 11 printable ASCII digits.If it starts to get close it is likely they will simply delete the videos that have fewer than x number of views over a period of time, after of course archiving them. Of course by that time there should be an AI around that will watch to see if the account holder is still alive, contact them or descendants and ask them first.

author: Noise Floor
author_rank: Regular Contributor
timestamp: April 25, 2015, 01:51:58 pm
content: Quote from: Psi on April 25, 2015, 12:11:35 pmHmm possibly. I obviously understand the lower cost of storage over time, but Google is still a business.Why continue to buy more storage to replace worn storage and add capacity for something that is never used? Perhaps buying more storage is cheaper then culling the useless data; that is an argument for "forever" storage that may make sense.With the ever increasing demand for video storage (presently >300 Hours uploaded each minute), I don't believe just because storage is cheap they will continue to spend money to store things no one uses.