So, if I'm not sure what ADSL I will have in the future, the best  option is to buy Cisco 887M because it has all ADSL options, isn't it?

Not said, in some countries Annex M will never be introduced. It's a local telco decision.

sorry, then the 887M is  the best option because it supports all kinds of ADSL, so with it I can not go  wrong with the choice of router. Will work with all. With one ISP with the other, ... Right?

Again, depends on where you are. You may find that distributors do not carry the M type your country, because local telco do not support it.

Thanks. But I say 887M is the best option (if you can pay for it) because if now my telco do not carry Annex M, I can connect with the 887M with AnnexA and if in the future my telco carry Annex M (or I change my ISP) I can connect wit 877M too (with Annex M or not). Right? But If now I buy a 887 (without Annex M), now I can connect to my telco, but if I want to change to a telco with Annex M in th future I will have to buy another router. Right?

Have you verified that 877M is avaialble for you to buy?

Find and report.

I have not yet verified (I'm in process). Why say that? Is  it hard to find?
Anyway, do you agree to my previous  statement?

"But I say 887M is the best option (if you can pay for it) because  if now my telco do not carry Annex M, I can connect with the 887M with  AnnexA and if in the future my telco carry Annex M (or I change my ISP) I  can connect wit 877M too (with Annex M or not). Right? But If now I buy  a 887 (without Annex M), now I can connect to my telco, but if I want  to change to a telco with Annex M in th future I will have to buy  another router. Right?"

Am I right?

Are you in the UK?

At the moment, Cisco doesn't support Annex M in the UK,

I woudl appreciate if you could avoid rating in the middle when what I'm telling you 100% correct.

Sorry, I'm not in UK

Thanks

So you mean that for example I can use an 887VAM with DSL ANNEX A ?