Sometimes my Linksys SPA-2102 NA does not generate "Ring back" (when calling my number a caller cannot hear ring back while my phone is rinning). Could you help?

SOURCE: password of linksys spa 2102

The Linksys comes with web admin access disabled.

To enable it, pick up phone, dial **** then 723646# , when asked for password, dial 78778839# , when asked for value dial 1# then dial 1 to save.

Then, go to »192.168.0.1/admin/voice/advanced , enter user and password.

If you did a factory reset, you will need to call Linksys technical support.

SOURCE: LinkSys SPA 2102

try this out
power on your linksys
then pick up the phone connected to that linksys
no dile tone required
dial ****
when it says configuration menu
type 73738#
if ask for password then nothing can help you buddy
and if it says press 1 to save then press 1 and your device is reset with factory default

SOURCE: I just bought a SPA-2102 NA, is it possible for a

Yes - if you set provision enable to "yes" or resync from SIP to yes, they can then set your SPA to download a configuration file with an admin password you don't know.
Seems pretty rude (as in legally actionable) if they have actually done this.