Analog/digital phoneline tester

[Vangelis Pantazis]

Hello everybody !
Can somebody tell me the technical difference between analog phone lines
(PSTN) versus digital ones (ISDN or aDSL) ?
Is there any way to distinguise them with an electronic device ?
I've heard of these digital phone line tester but I'm not sure if this is
the one I'm looking for to build.

Any ideas ? Many thanks, in advance

V.P.

 

[Van Gardner]

Hello everybody !
Can somebody tell me the technical difference between analog phone lines
(PSTN) versus digital ones (ISDN or aDSL) ?
Is there any way to distinguise them with an electronic device ?
I've heard of these digital phone line tester but I'm not sure if this is
the one I'm looking for to build.

Any ideas ? Many thanks, in advance

V.P.

I have such a device made by IBM called a Line Current Checker P/N
16F1621. They came out with the device about 15 years ago when laptop
computers and digital phone system were meeting in motel rooms. If
you plugged one of these early laptops into a digital line it would
blow up the modem. The analog line is current limited to 100ma and
the digital is not. The device is 5 1/2 inch long and 1/2 inch square
with a clip to wear in your shirt pocket. It has a RJ11 phone plug on
one end to plug into the line you want to test. It has three LEDs
that are powered by the phone line. The first light (green)is labeled
OK and indicates that current is limited to 100ma or less. The second
light (Red)indicates current not limited, over 100ma. The third light
(green) labeled REV indicates that the tip and ring wires are
reversed. This device does not indicate performance of the line but
lets you know what type line it is before you plug your laptop in.

Van Gardner

 

[geo73]

I think he wants to built one, not to buy.

You can alternatively use the following troubleshooting procedure:
You enter the customers place, you ask what line do they got,
you plug the appropriate telephone and do your checks.
Works for PSTN and ISDN, ADSL is only installed and serviced
by OTE Vivodi etc.



George

 

[inuyasha]

Hello everybody !
Can somebody tell me the technical difference between analog phone lines
(PSTN) versus digital ones (ISDN or aDSL) ?

the actual wires are plain old telephone wires. my adsl connection is
with very old house wiring. It's just the second phone line (second
pair) really.

They just use a digital modem instead of an analog modem.

Is there any way to distinguise them with an electronic device ?

I'd imagine you'd get a dial tone off the analog line, just hook up a
cheap phone

 

[Vangelis Pantazis]

Hello ! Thanks for the reply.
Since someone asked for it for ease of use, I can't just tell him to plug a
phone and see if it works.
I must somehow build something.
But at least I got the idea what I'm looking for (from the previous
message).

Thanks again !

: I think he wants to built one, not to buy.
:
: You can alternatively use the following troubleshooting procedure:
: You enter the customers place, you ask what line do they got,
: you plug the appropriate telephone and do your checks.
: Works for PSTN and ISDN, ADSL is only installed and serviced
: by OTE Vivodi etc.
:
:
:
: George
:
:

 

[Vangelis Pantazis]

Hmm... sounds interesting.
Now at least I understand how it works. Thanks alot!

: > Hello everybody !
: > Can somebody tell me the technical difference between analog phone lines
: > (PSTN) versus digital ones (ISDN or aDSL) ?
: > Is there any way to distinguise them with an electronic device ?
: > I've heard of these digital phone line tester but I'm not sure if this
is
: > the one I'm looking for to build.
: >
: > Any ideas ? Many thanks, in advance
: >
: > V.P.
:
: I have such a device made by IBM called a Line Current Checker P/N
: 16F1621. They came out with the device about 15 years ago when laptop
: computers and digital phone system were meeting in motel rooms. If
: you plugged one of these early laptops into a digital line it would
: blow up the modem. The analog line is current limited to 100ma and
: the digital is not. The device is 5 1/2 inch long and 1/2 inch square
: with a clip to wear in your shirt pocket. It has a RJ11 phone plug on
: one end to plug into the line you want to test. It has three LEDs
: that are powered by the phone line. The first light (green)is labeled
: OK and indicates that current is limited to 100ma or less. The second
: light (Red)indicates current not limited, over 100ma. The third light
: (green) labeled REV indicates that the tip and ring wires are
: reversed. This device does not indicate performance of the line but
: lets you know what type line it is before you plug your laptop in.
:
: Van Gardner