The connectors

The figure below shows the connectors on the rear of the Group Telepresence 3330 (GT Mini) codec.

The table below describes the connectors:

Connector Description
Microphone XLR-F connectors. Connect the microphone. You can alter the power and gain settings of the microphone via the StarLeaf Portal (refer to Audio settings for Group Telepresence)
Audio line-in 3.5mm line level stereo audio connector. You can connect a line level microphone source or input other audio, for example a computer. In either case, ensure you have the correct settings for audio in the Portal. For more information, refer below and to How to install GT Mini 3330
Audio line-out 3.5mm stereo audio connector. If required, you can connect to a local loudspeaker system. You can alter the line-out audio settings via the StarLeaf Portal (refer to Audio settings for Group Telepresence). For more information about the connector, refer below this table
COM This port is for a 4P4C connector providing an RS-232 interface. This is the same connector used in RJ9, RJ10, and RJ22. There is both a serial and an IP API option for the GT Mini and a StarLeaf Room Systems API guide is available
Camera control Mini-DIN-8 connector for controlling zoom, pan, and tilt using VISCA™ protocol. You connect to this port if you are using a PTZ video conferencing camera. For more information, refer to About the camera
Camera input HDMI connector. You connect to this port if you are using a PTZ video conferencing camera. For more information, refer to About the camera
Computer In DVI-I connector. Connect a PC or other device to share content in a video call or locally. If audio-in is enabled on this connector, audio can also be shared from the connected device when connected using an HDMI-DVI-I connector. From Cloud 7.1, audio-in on this DVI-I connector is enabled by default. If your room system pre-dates Cloud 7.1, contact StarLeaf Support to enable audio-in on this connector
Video Out HDMI x2 HDMI connectors. Video Out connector A outputs both audio and video (1080p60 only) to the screen. If you are connecting a second screen, connect it to HDMI port B
USB x2 USB connectors. If you are using a USB webcam, you connect it to one of the USB ports
Network 10/100/1000 Mbit/s auto-sensing Ethernet port. Connect to the network
StarLeaf Controller Only Connect to the PoE port on the rear of the StarLeaf touchscreen controller to both power the touchscreen controller and to allow communication between the touchscreen controller and the codec
+48V power Connect to the supplied AC/DC adaptor

There are LEDs on the Network port and the StarLeaf Controller Only port of the codec indicating the status of the network link, and the link to the StarLeaf touchscreen controller. LED behavior is described in LED behavior.

Older models of GT Mini have HDMI ports labeled 1 and 2. In this case, plug screen 1 into port 2.

Using the correct HDMI and DVI cables

When connecting HDMI or DVI cables to the camera inputs, the PC input, and the telepresence screen display outputs, ensure you use the correct gauge of HDMI/DVI cable. For short cable lengths of up to 5m (17 feet), use 28AWG or thicker core. For longer lengths, use 24AWG or thicker. StarLeaf does not support the use of HDMI or DVI cables of longer than 15m (49 feet) with the codec.

Audio connectors

Audio voltage levels

If you are using external equipment to connect the GT Mini to your microphones, you need to be aware of the required audio voltage levels for XLR, audio line-in, and audio line-out:

  • XLR Mic in sensitivity -40dBu to -13dBu (The StarLeaf Portal 0dB gain setting is equivalent to -13dBu)
  • 3.5mm Line in sensitivity -16dBu to +12dBu (The StarLeaf Portal 0dB setting is equivalent to +7dBu)
  • 3.5mm Line out range -40dBu to +2 dBu (The StarLeaf Portal 0dB gain setting is equivalent to +2dBu)

 Phantom power is compatible with active microphones that are designed for 48V phantom power. The following are specifications of the power supply:

  • Output voltage when operational, no load is 45.3V +/- 4%
  • Output voltage when muted, no load is 35.3V +/- 4%
  • Power output source impedance is 1.975kOhms +/- 2%

3.5mm audio connector pinout

All StarLeaf room systems use a standard 3.5mm connector:

Left signal = tip

Right signal = middle

Ground = back

Extending the camera cables

StarLeaf room systems that use a PTZ camera are provided with camera connection cables of 5m in length. If you need to install the camera further than 5m from the room system, you must extend those cables.

You can extend those cables using a third-party product called an extender. This product effectively carries the media and camera-control signals across a cat 6 Ethernet cable.

StarLeaf has partnered with Sound Control Technologies to provide this solution which is available at

CEC support

CEC is supported by GT Mini 3330 as a beta feature. If you want to enable CEC support on your GT Mini 3330, contact Starleaf Support.

CEC allows the GT Mini to communicate control commands to the connected screen/s across HDMI. When enabled, it will put the screen/s to sleep in between calls. GT Mini will wake the screens when it receives, or you make, a call. If the screens are displaying from a different source when GT Mini receives, or you make, a call, GT Mini will tell the screens to switch the source to GT Mini.