ADSL with ISDN

[nic777]

Hi,

I need to install a ADSL line so we can get a always-on 512K connection to the Internet. We currently have a ISDN connection and I would like to install the ADSL line with minimal fuss and maybe even keep the ISDN line.

Is it possible to have ADSL running 'through ISDN'? I know you can't run ADSL over the digital lines of ISDN but I know there's ISDN2a and TA for ISDN which provide analogue ports - can these be used to install ADSL?

Thanks
Nic

 

[gripen]

Probably not. ADSL is an end to end service meaning the line must be analog (roughly speaking) from you to the exchange. ISDN means your line is connected to a digital port at the exchange. Your ISDN2a converts digital to analog for voice and vice-versa. Dialling into your 2a ports with a modem works fine since a modem transmits effectively a sound like voice which converts to digital just fine.

Yes, ADSL is Digital but how it works is that the digital stuff is sent at a higher frequency on the same line as your voice signal ie. the analog line. ADSL pretty much piggy backs on your analog line and filters are used to "separate" the low frequency analog voice signals form the higher frequency data or digital signals.

The above is a simplification. But for explanatory purposes, analog and digital will suffice in this context.

So, no I doubt that you can get standard ADSL over ISDN without modifications to the DSLAM etc. I do know that it is possible but Telkom probably does not supply it. Maybe ask for VDSL

There was a topic on this farily recently.. maybe do a search

 

[Brannor]

So, if I'm upgrading from ISDN2a to ADSL...it really should be a simple as the techie unplugging the ISDN box, and plugging in another box for ADSL?

-G

 

[gripen]

Yes. They will probably have to re-test your line also. It should be simple.. However, that doesnt mind it costs less or wont take as long. You still have to wait your 21 days. And pay your R404.

Remember, Telkom charges R85 or something for a re-connection which is pretty much a click of the mouse.

 

[Darth Garth]

So, if I'm upgrading from ISDN2a to ADSL...it really should be a simple as the techie unplugging the ISDN box, and plugging in another box for ADSL?

Just make sure it states an ISDN2a to ADSL line conversion on your application form.

I did the same conversion and the technie disconnected my ISDN line in the morning and swapped it out at the exchange from an ISDN port over to the ADSL port.

He pitched up 2 hours later and removed the ISDN box from the wall and then plugged the telephone line into his ADSL modem and fitted a filter for isolating my two telephones.

 

[Celemasiko]

Hi,

I need to install a ADSL line so we can get a always-on 512K connection to the Internet. We currently have a ISDN connection and I would like to install the ADSL line with minimal fuss and maybe even keep the ISDN line.

Is it possible to have ADSL running 'through ISDN'? I know you can't run ADSL over the digital lines of ISDN but I know there's ISDN2a and TA for ISDN which provide analogue ports - can these be used to install ADSL?

Thanks
Nic

It is possible, but not here in SA. You will need a special device which is splitting the analog signal (DSL) from the digital signal (ISDN). This is as far as I know not yet available here...

 

[Darth Garth]

It is possible, but not here in SA. You will need a special device which is splitting the analog signal (DSL) from the digital signal (ISDN). This is as far as I know not yet available here...

It is mainly a German solution afaik ... also ADSL over ISDN requires an ADSL modem that supports Annex B standard (Annex A is ADSL over POTS).

 

[nic777]

thanks for all the replies.

 

[FireFLi]

I upgraded from ISDN2a to ADSL without a problem and now I am saving myself a wad cash every month.

 

[DFantom]

Is it possible to have ADSL running 'through ISDN'?

Here we hit theory vs. reality. As greedyflyza stated so nicely in SA you are screwed by Telkom so you can't. However in the realm of theory, there is a system called IDSL which is exactly ADSL over ISDN lines. Which could work well, but reality bites and Telkom sits on it's ass

 

[francois9]

Why would anybody want ISDN and ADSL at the same time????

 

[nic777]

1 Example: Use 200kbps ADSL line for ftp server and ISDN for phone calls, faxes.