Please find your device by the picture. Once located you will need to know if you are connecting to a Standard Modem or a Modem/Router Combo, you can find those here:
Standard Modems
Modem \ Router Combination
If your device is a Zyxel or SmartRg make sure to plug your phone directly into Phone 1 or VOIP 1.

Cisco Spa 122

Normal Light Status

From Bottom to Top Power On/Solid, Globe On/Flashing, Phone 1 ON/Flashing if on active call, Phone 2 ON if they a second line/Flashing if on active call

Cisco Spa 2102

Normal Light Status

From Bottom to Top Power On/Solid, Globe On/Flashing, Phone 1 ON/Flashing if on active call, Phone 2 ON if they a second line/Flashing if on active call

It is extremely important that these devices are connected properly.
For Help connecting your ATA to a modems see below:

To connect to standard modem

To connect to Modem / Router combination