[Year 12 IT Apps] VITTA ITA exam 2 - my ideas of errata

[Kevork Krozian]

Hi again Mark,

> Hmmm!  The "D" in (A)DSL is a bit of a distraction then!

 The D is a distraction in so far as the digital component starts at the DSLAM ( exchange ) and onto the internet backbone. Customer premises to exchange is still analog.

> Does this mean that ISDN is therefore also not really digital?

Great question about ISDN ...

By contrast ISDN ( Integrated Services Digital Network ) is digital all the way from the customer onwards. A special "digital" phone line is needed to set up ISDN. No such special line is needed to get your ADSL service up and running.
One can plug a normal analog phone on an ADSL link but not on an ISDN link. Another device called a Terminal Adapter sits between an analog phone and the ISDN service.  The ISDN and non ISDN devices have different voltages.
Interestingly ISDN is only a fallback/emergency type of service these days and not the primary choice of WAN link for organisations. The most common WAN technologies now are DSL and leased lines. 
Most of this is knowledge covered in Semester 4 of Cisco CCNA - a VET subject . I don't own any shares in Cisco systems for the record, but teaching the course has made my configuring, understanding and troubleshooting of networks so much clearer....... 

I think this is much more than ITA and more than SD frankly, but very useful, just like how to fix your car, 
how to cook a nutritious meal and how to win friends and influence people through humour, sarcasm or anything else that works .........  :))


Keep well

Kevork