FTTC Router Sync Status

'Sync' is your modem's ability to talk to your local green cabinet. Most, if not all, modems/routers will have a LED that shows the sync status. This is often the LED labeled DSL, and generally speaking on is in sync, and flashing or off means no sync.

This is a table of popular VDSL/FTTC modems and routers and how you can tell if they are in sync or not by looking at the LEDs on the device. You can often gain more information by looking at the diagnostic pages on the router's web interface, but this will help you tell at a glance if the modem is in sync or not.

This can help diagnose a fault, as if the router is not in sync then the problem lies between the router and the your local green cabinet. It could be:

• the router
• the wiring between the router and the main phone socke
• a problem with the actual phone line between you and the cabine
• or even a fault with the cabinet itself.

It does mean though, that the fault is unlikely to be with your computer or your internal network.

Modem/Router	Sync LED Label	In Sync	No Sync	Notes
Openreach Modem	DSL	On Green	Flashing green or off	ECI or Huawei
VMG1312	DSL
Technicolor TG589vn	DSL
Billion 8200N	DSL
DrayTek Vigor 2760n	DSL
FRITZ!Box 7390	DSL
Asus DSL-N66U N900	DSL