What Modulation Type should my router be set too?

[#1]

Hi All,
What DSL Modulation should I have my router set to?
I am on a standard ADSL line getting around 9Mbps.
Thanks

[#2]

automatic

[#3]

Thanks for the response.
The router was set to 'Auto-Sync' but reading a few other posts it mentioned that this could cause problems.