# Telemedicine: A Survey of Telecommunication Technologies, Developments, and Challenges
## 3 Overview of Telemedicine
In live telemedicine, audio-visual communications over high bandwidth and low latency connections involve the presence of both the patient and the doctor, while store-and-forward involves the acquisition of medical data, images, and video transmission by a medical expert for offline diagnosis. Telemedicine involves the use of ICT, especially two-way interactive audio/video communications, computers, and telemetry, to deliver health services to remote patients and facilitate information exchange between primary care physicians and specialists located at a distance from each other [26]. Alternatively, telemedicine can be seen as the use of advanced telecommunications technologies to exchange health information and provide healthcare services across geographic, time, social, and cultural barriers. To appreciate the concept of telemedicine and how patients are connected to remote caregivers, Figure 2 provides a helpful illustration. The backplane is the main centre of connection to the other components, while the User Interface and the video conferencing device are linked by the control set to the backplane. Through the backplane, information is transmitted from the patient unit to the care giver unit over the communication channel of the communication device, as well as vice versa. The items represented by the block diagram describe the services, as follows [44]:  
1. User Interface Device: this is the device that the patient or healthcare provider uses to access the telemedicine system; it could be a smartphone, tablet, computer, or any other device that has an internet connection. 2. Communication Device: this device is responsible for establishing and maintaining the communication channel between the user interface device and the virtual medical device; it could be a modem, router, or any other networking device that can transmit data over the internet
3. Communication Channel: this is the pathway through which data are transmitted between the user interface device and the virtual medical device; it could be a wired or wireless connection, depending on the type of communication device being used. 4. Video Conferencing Device: this is a feature of the telemedicine system that enables live video and audio communication between the patient and healthcare provider; it allows for real-time interaction, examination, and diagnosis
5. Control Set: this is a set of rules that governs the transmission of data over the communication channel; it ensures that the data is transmitted in a secure, reliable, and efficient manner. 6. Protocol: This is a set of rules that govern the transmission of data over the communication channel. It ensures that that data are transmitted in a secure, reliable, and efficient manner. 7. Backplane: this is the backbone of the telemedicine system that connects all the components together; it provides a high-speed and low-latency connection that enables real-time communication and data transfer. The backplane presents two kinds of interface to the system, namely, registry interface and object-supporting interface. The registry interface notes when parts join the system, change their inner state, or leave the system. Protocol components use registry data to find resources required for their activities. The object-supporting interface contains objects that aid local communications. 8. Virtual Medical Device: this is a device that simulates the functions of a physical medical device; it could be a software program that runs on a computer or a specialized device that connects to the telemedicine system, and allows for remote examination, diagnosis, and treatment of the patient. 9. Medical Device: this is a physical device that is used to examine, diagnose, or treat the patient; it could be a blood pressure monitor, stethoscope, or any other medical instrument that can be connected to the telemedicine system. 10.