Connection #1:

Any one of these telephone connections:

• Analog telephone line
• DSL with digital filter
• PBX system with analog port

For outgoing calls, simply dial the other party directly.

For incoming calls, the other party first dials a toll-free captioning service then enters your phone number in order for their calls to be captioned for you. 

Connection #2 (optional)

• Second analog line
  or
• DSL with digital filter

This optional second phone line enables the other party to dial your number directly with the captioning service automatically connected.  For outgoing calls, simply dial the other party directly.