Hello,
Can anyone please explain what is the context of the 'Digital PSTN Network' & 'ISDN Office' in the diagram below? Also, what is beyond the 'Digital PSTN Network'? I am not able to understand the implementation and placement of ISDN in real-life networks. Like where is it used and why is it used?
Thank You 
ISDN provides WAN access to a digital telephony network. The ISDN PRI to the business can be divided into 23 different lines, So no more than 23 connections at any one time. Because it's a complete digital run from the local loop through the network with no analog in between the business and digital network.
If you're needing to insure that your digital telephony has dedicated bandwidth, ISDN is the technology for you.
Cordially,
Ronnie Wong
Edutainer Manager, ITProTV
*if the post above has answered the question, please mark as solved.
**All "answers" and responses are offered "as is" and my opinion. There is no implied service, support, or guarantee by ITProTV.
The bandwidth for Basic Rate Interface ISDN would be used for residential connections, Primary Rate Interface ISDN with the higher bandwidth and expense was typically used inside of the telecommunication providers network and larger enterprises. Remember this was a time with 56Kbps dialup modems where the most prevalent connections at the time, so when ISDN provided two bearer channels (B Channels) at 64 Kbps, the customer would get a 128Kbps connection speed. If you where a larger organization you could get a combined speed of 1.54Mbps (with the 23 B channels that Ronnie mention earlier), with the ability to have more simultaneous parallel communications, as well as being the first converged communication technology (carrying voice, video and data over the same medium).
Best Regards,
Wes Bryan
Knowledge is a road to be traveled upon, not a destination to be reached~~
