SourceVoice Carry Over
The next most common call type is Voice Carry Over (VCO). VCO allows a person who is Hard–of–Hearing or Deaf and does speak to use one's voice while receiving responses from a person who is Hearing via the operator's typed text. There are many variations of VCO, including 2-Line VCO and VCO with privacy.
You can use VCO with VP as well. Sorenson, HOVRS, CSDVRS, and Sprint all allow VCO.