The technology behind video calling on Physitrack

The video calling technology that Physitrack uses is provided by  TokBox, a subsidiary of Vonage, a business VOIP provider.

Every video call occurs within a session. You can think of a session as a “room” where callers can interact with one another in real-time. Sessions are hosted on the OpenTok cloud and manage user connections, audio-video streams, and user events (such as a new user joining). Each session is associated with a unique session ID. Detailed technical overview here.


All media traffic is encrypted no matter the endpoint you use (web or mobile). That means that you are safe when using OpenTok even if use it in an open public hotspot.

OpenTok is fully based on proven standards, written by industry experts, and used for years in commercial products. The core protocols providing WebRTC OpenTok security are SRTP for media traffic encryption and DTLS-SRTP for key negotiation, which are defined by the IETF.

OpenTok WebRTC-compatible endpoints use the AES cipher with 128-bit keys to encrypt audio and video, and HMAC-SHA1 to verify data integrity.

The endpoints generate random keys at the beginning of the session and in addition they change periodically during the conversation to make it even safer.

Note that media streams are temporarily decrypted while within the OpenTok Platform cloud servers and then immediately re-encrypted prior to being sent through the internet to the client. This decryption is necessary for recording of sessions (if enabled). Your media streams are never transmitted unencrypted on the open internet.


Recordings/archives of calls

Physitrack can enable the possibility for PT Direct accounts to record the audio portions of all calls made by practitioners that belong to this PT Direct account.

These recordings are stored on Physitrack's private AWS S3 storage, and are deleted if and 0when the PT Direct account is deleted.

System requirements

Please see the video calling system requirements.

Audio & video quality

Audio and video quality is set automatically by the platform, taking into account your available hardware and bandwidth. Audio has priority over video.

To test your audio & video quality, please click the TokBox Pre-call test link below.


  1. If you are experiencing trouble with a client or degraded video and audio quality, please conduct the TokBox Pre-call test to check that both your and your client's network support TokBox.
  2. For your network administrator: TokBox Network Requirements
  3. If your practice or your clients are behind restricted networks (such as banks, insurers and hospitals) that block and filter internet traffic, please ask your network administrator to review the  TokBok restricted network troubleshooting flowchart.

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