AnnexB --> Annex A on ADSL2+ : yes and no

[psmammoth]

Hi,

I've converted a 7140 annex B to annex A as described in several posts over here.
Does it work : yes
Do you get a good result on ADSL2+: no

I've an ADSL2+ Annex A line with a distance of 3,4 km and with a -native- Annex A Speedtouch 780 WL I get a synch down/up speed of 7Mbit/1.1Mbit which is quite normal for this distance. With a converted fritzbox 7140 I only get 0,5Mbit/0,8Mbit (yes, lower down then up)

As an experiment I replaced the ISDN trafo inside the Fritzbox with an PSTN trafo. This trafo was from a Speedtouch which has a Broadcom chip instead of an Infineon chip so still not ideal. This way I reached 2Mbit/1Mbit, so still far from what a native Annex A modem would reach.

Best regards,

Paul.

 

[imagomundi]

It is described in all the relevant threads all over in this forum that an FB original "B" converted to "A" is FAR from doing the same good job than an original "A"-box!! Additionally: Poor qualitity dsl signal worsens this effect. A certain exception seems to be the 7270 that uses the same modem for A and B.

 

[psmammoth]

It is described in all the relevant threads all over in this forum that an FB original "B" converted to "A" is FAR from doing the same good job than an original "A"-box!! Additionally: Poor qualitity dsl signal worsens this effect.

Yes sure, I just wanted to emphasize that for ADSL2+ a modified annex B to A is simply useless. I tried with an ADSL connection as well (same distance, 3,4 km) and here I could get the normal sync speed (4Mbit/512Kbit) (with a higher number of CRC errors).