Hello Friends,
Here is a shot in the dark on Cisco SOHO or Branch Cisco Routers savings that is easy to see and make. As well as a bit of easy future proofing on Cisco ADSL Routers with Annex A ( Standard ADSL ) and Annex M ( Faster! ADSL ). So, it occurred to us that today was an opportunity to see if we can learn something new? Well I tried…
My questions was: Can an Annex M ( Fastest speeds before Fibre ) Cisco Router work on the slower Annex A ( Standard ADSL ) lines? Are they downward compatible, and Auto-Sensing?
Answer: Yes.
Firstly, Cisco800 routers that support Annex M can be identified by a “M” in the product name, for example CISCO887M-K9. Cisco887M Data Sheet
Secondly, Annex M routers are able to Auto-Sense between Annex M and Annex A, where Annex M is available. However, an Annex A router can work only on Annex A.
If a Cisco Router supports both Annexes, you can use the interface command “dsl operating-mode” to force a specific Annex (default is auto mode).
Have a look below and you can refer to this for router specifications:
So in simple terms a Cisco887M-K9 Router will act on Annex A and M lines, and a Cisco877-K9 will act on Annex A.
Additional bits for insomnia on Annex A, and Annex M – links are below.
http://en.wikipedia.org/wiki/ITU_G.992.5_Annex_M
http://en.wikipedia.org/wiki/Asymmetric_digital_subscriber_line
Until next time,
Matt





