The OBi 202 is an ATA that supports four independent Service Provider (SP) configurations (e.g. any combination of Google Voice and/or Callcentric). It has two physical phone ports (female modular phone jacks). Depending on the type of connections on your two-line telephone, you can either use a 4-conductor, RJ-14 cable, plugged into the PHONE 1 jack or 2, 2-conductor RJ-11 cables, one plugged into each of the two jacks. PHONE 1's outer two pins are electrically connected to the two center pins on the PHONE 2 jack, to make this possible.
What you refer to as "Google Chat" is now simply Google Voice over SIP. Chat (XMPP) is being shut down.