Integration of CCTV Cameras and AVoIP System for Interrogation Training Center in the UK

Integration of CCTV Cameras and AVoIP System for Interrogation Training Center in the UK


In order to effectively obtain evidence/ information used in criminal proceedings, the UK police department has been delivering professional training like PACE (Police and Criminal Evidence) and ABE (Achieving Best Evidence) to UK police officers. In the training, the officers will understand the below items to optimize the interrogation process.

  • How to effectively maximize memory recall.
  • The key differences between suspect and witness interviews.
  • How to use the PEACE/ ABE model to effectively manage an interview.
  • Questioning techniques.
  • How an interview under caution can be used within both criminal and civil law.


In this case, the department intended to build a training system with 4 training rooms and 3 classrooms.

Each training room has

  • two AHD cameras, (one is fixed and the other is a pan-tilt-zoom camera)
  • one stereo microphone that allows the trainers to speak with the trainees in different classrooms.

While each classroom has

  • a large-format HDMI input monitor
  • a PTZ camera controller

From any of the 3 classrooms, the trainer needs to be able to display any of the 4 training rooms, with the two cameras from the selected room as PIP (picture in picture), and use an RS485 pan-tilt controller to control the camera in the selected room.

SC&T's Solution


4K HD-TVI/ AHD/ HDCVI/ CVBS to 4K HDMI converter converts AHD to HDMI signal to integrate two AHD cameras into the A/V  over IP system while allowing watching in PIP mode.


4K HDMI KVM over IP extender, allowing to switch videos between classrooms and the interrogation training rooms.

Gigabit Ethernet Switch

To connect HKM02BT-4K and HKM02BR-4K


Same as HKM02BT-4K


RS485 to RS232 bi-directional converter allows one PTZ controller to operate the PTZ cameras over IP.

Distributed A/V System

An A/V system consists of multiple sources and displays and typically requires a matrix switcher to route videos to different displays. However, the AVoIP technology is a more ideal solution to build a distributed A/V system. With high flexibility and scalability, the system can freely expand its sources and displays from time to time. Click HERE for more details.

The system integrator set up four HKM02BT-4K (transmitter) for AHD cameras, and three HKM02BR-4K (receivers) for HDMI input monitors, along with a 1G Ethernet switch to build the system, allowing the trainers and trainees to freely switch the desired video between four training rooms.

AHD Camera to HDMI

From the camera end, AHD cameras need to be converted to HDMI signals to integrate with the AVoIP system. AD001HD4-4K is the perfect solution for it. It connects one AHD camera via the input port and uses the loop-out port to connect the other camera to convert both AHD signals to HDMI. With two videos in the converter, the PIP function can be enabled to meet the requirement of the project.

Audio Integration

The AD001HD4-4K also has a built-in audio input to connect a CCTV Microphone and turn the audio with AHD into an HDMI signal, eventually transferring it to the audio system in the classrooms over IP. With the audio feature, the converter makes the communication between spaces more efficient and smooth.

Pan-tilt-zoom Control

Since every classroom requires a controller to adjust the PTZ cameras in four different rooms, the RS001 (RS485 to RS232 bi-directional converter) allows the controllers to integrate with the AVoIP system to operate the PTZ camera in the selected room.


The installation requires exceptional experience in both CCTV and pro A/V fields to arrange the system. With the expertise of David Horn Communication LTD and the SC&T custom solution, the project is completed in an easier and faster way with 34% budget saved, most importantly satisfying the customer with an easy-to-use system.

We've provided over 300 items for CCTV and pro-AV applications, and the ideas of these products are derived from users' and installers' problems. We deeply believe that cooperation is the foundation of a win-win situation, and happy to offer you not only a product but a way that makes things easier.

November 28, 2022

Cable Used

Product Name


Power Source



1080p Distance

4K Distance

Optical Fiber Cable

HDMI Fiber Cable


(Reflection of Light)

Power From Source

Video/ Audio




HDMI Fiber Dongle Extender

Mini USB


300M/ 1KM

300M/ 1KM

Network Cable

HDMI CAT5e Dongle Extender


Power From Source

Video/ Audio




HDMI CAT5e Extender

External Power Supply

Video/ Audio




HDMI over IP Extender

Internet Protocol

External Power Supply

Video/ Audio




HDMI KVM over IP Extender*

Video/ Audio/ Keyboard/ Mouse



HDMI Cable

HDMI Repeater


External Power Supply

Video/ Audio




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