From: lim@merlion.CWRU.Edu (Hock Koon Lim)
Newsgroups: soc.culture.singapore
Subject: Re: S`poreans own Modems
Date: 25 Jan 1993 22:35:32 GMT
Organization: Information Network Services, Case Western Reserve
Distribution: world
Reply-To: lim@po.CWRU.Edu
NNTP-Posting-Host: merlion.ins.cwru.edu


In article <1993Jan25.210937.13681@bmers95.bnr.ca>, khor@bnr.ca (Kyle Hor) writes:
$ In article <1993Jan25.174512.1768@nuscc.nus.sg>, law30056@nusunix1.nus.sg (TAN KEN HWEE) writes:
$ |> TEE LUNS (tee@ecf.toronto.edu) wrote:
$ |> : In article <1993Jan23.173121.17930@nuscc.nus.sg> isc20390@nusunix1.nus.sg (CHONG KAH YUEN) writes:
$ |> : >Errrr.. The idea is to have ISDN in Singapore (by 2000 AD) thats the
$ |> : >idea... when , how and who will have the system up is still not confirm.
$ |> : 
$ |> :    Hmm.. I remember distinctly, an exhibit at the Singpoare Science Centre
$ |> : in the Lower Exhibition Hall of the OmniPlanetarium/OmniTheatre building
$ |> : (the area where you lounge around waiting to see the Omni-Theatre movies).
$ |> : It was about ISDN, and it claimed that Singapore already has completely
$ |> : implemented the first stage of ISDN - i.e. everything between switching
$ |> : stations - and that you can get terminal adapters which convert what the
$ |> : switching station sends to the plug in your wall back into digital. What
$ |> : was not yet implemented was the second stage - that of converting the
$ |> : analog user-lines over to digital so that the terminal adapters are no
$ |> : longer necessary: you get digital data right out of your wall.
$ |> :
$ |> Methinks that's correct.  It's a matter of time.  I think 5 years should
$ |> be about it.
$ |>  
$ ISDN requires 4 wires.  Open up your phone jack and check if you
$ have 4 or more wires.  Given S'pores efficiency coversion could be
$ just a blink away.  But if you have only 2 wires...that is another
$ story.
$ 
$ ...Kyle
$ 
$ 

   The ISDN line that I am using from Ohio Bell only need two lines from the
central office.  It is a regular phone wire that I have been used for the
last few years - 24 AWG.  The phone company does not need to change the existing
copper wire at all.  What they need to change are the hardware or software in
their switch at the central office.  

  The "two wire" that comming from the central office is refering as "U"
loop in ISDN terminology.  The "U" loop will connect into a device 
refering as "NT1 Power Supply Unit" which provide power and signal to
the "NT1" through the "U+" interface.  The "NT1" has another interface call
"S/T Loop" which is connected to the "ISDN Terminal/system adapter".
The system adapter can be an external or internal device (eg. Apple computer's 
NuBus ISDN card and Hayes's ISDN system adater(external).  The external 
ISDN adater usually has a RS232 and a two wire phone interface which you can
use for data and handset of a regular phone.  The cost of the terminal adater
is about $1000+ dollars.

  The "U" interface only need two wires and the "S/T" interface use 4 wires.
Usually, the interface is a 8-position modular jack(RJ45s).  Its pinout and
operational parameters follow the CCITT I.430 standard.  Pin 1,2,7,8 not used.
Pin 3,4,5,6 (transmit(TE to NT), receive, receive, transmit).  Both the 
NT1 and NT1 power supply unit are provided by the phone company.  Users
need to buy their own terminal/system adater as the phone company are not
allow to sell customer premiss equipment (CPE) in US.  I am not sure what 
Singapore Telecom provide to it customer but I would guess they will 
provide you with both NT and TE.  From what I have read, ISDN services is
available for all customers in Singapore if you want to pay for the rate.