On 10/8/23 8:14 AM, Marco Moock wrote:
> What are exactly these ISDN boxes referred in the article?
You seem to be describing a NT1, which converts from the 1-pair BRI from
the telco to the 2-part, multipoint, ST bus. The phones and routers were
on that ST bus.
But here, many ISDN installations used a single box with both parts
within it; it terminated the BRI, and also provided a router and/or POTS
jack.
The outside box might have been a NT1, or more likely the overvoltage
"protecter" on any line entering a building. It shunts a lightning
spike, etc. to ground.
Unlike the EU, US ISDN was an overall failure. It got use in several
specific markets; it was popular for radio broadcasters on remote
broadcasts, offering dual dependable, noise-free circuits without
expensive point-to-point leased circuits. Classical music stations loved
it.
Other users include large Centrex accounts. ('Centrex' was a PBX-like
telco offering, offering 4-digit dialing within the company, and each
phone has its own 10 digit number. The switching was done by the Central
Office switch.) ISDN Centrex allowed phones with multiple-line buttons,
and other features. Centrex was very popular with US Government offices
in the DC region, because many agencies are sprawled over multiple
buildings, yet every fellow employee was a 4-digit dial away.
But residential ISDN phone service was not a success here; the Bells
regarded it as a premium service, and priced it as one. It was used for
Internet dialup, as its 64Kbs was better than a 28.8Kbs modem; it was
soon surpassed by DSL and Cable modem data.