ADSL2+: ISDN or POTS

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Henry
Beiträge: 32
Registriert: 24 Feb 2005, 10:11

ADSL2+: ISDN or POTS

Beitrag von Henry »

Hello,

We are about to replace our 1621 for a 1721 with ADSL2+ but somewhere I heared a rumour that ADSL2+ over ISDN couldn't reach the speed POTS can, and because we need another line this is the time to find out. Is this true or just a hoax?

Regards,

Henry
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MoinMoin
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Beiträge: 1979
Registriert: 12 Nov 2004, 16:04

Re: ADSL2+: ISDN or POTS

Beitrag von MoinMoin »

Hi Henry!
Henry hat geschrieben:We are about to replace our 1621 for a 1721 with ADSL2+ but somewhere I heared a rumour that ADSL2+ over ISDN couldn't reach the speed POTS can, and because we need another line this is the time to find out. Is this true or just a hoax?
Annex A (POTS) uses up to 480 bins for downstream and up to 26 bins for upstream (with up to 15 bits per bin and 4000 Hz symbol rate), Annex B (ISDN) up to 448 for downstream and up to 32 for upstream.

So there is a difference. If you use rate adaptive ADSL and don't get the full rate, I would expect Annex A to be a little faster in downstream direction - up to some hundret kilobit/s maybe.

You should ask your telephony company.

Ciao, Georg
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