An Interface is a common shared medium across which two different components of a computer system can exchange data or information.
There are basically two types of interface:
- Hardware Interface
- Software Interface
Majority of equipments which do processing of data contains a relatively restricted capability in terms of transmission of data. It is very uncommon that these devices can be connected directly to a network layer device. These devices include terminal devices as well as PCs comes in this category and are commonly known as Data Terminal Equipment (DTE). However, this DTE alone cannot do a data exchange without the help of Data Circuit terminating Equipment (DCE).
There is a requirement of a great level of mutual understanding for exchanging data between two devices linked by a transmission medium. This role is fulfilled by the DCEs which act as a mediator between two DTEs and offers the desired command over the communication between both DTEs and the data bus. It should be noted that the rate/spacing/duration of the data pieces (bits), and the encoding and decoding format should be exact for both transmitting device and receiving device.
It is therefore we can say that a Data circuit terminating equipment (DCE) has two basic functions.
- It carry out data exchange through a networking path.
- It communicates with DTEs and passes on the data.
These functions are performed by the DCE over a configured bunch of cables which we know as Interface.
So an interface has four important characteristics:
- Mechanical characteristics – It describes the physical configuration of the DTE and DCE.
for example –
(i) It describes how the various data control circuits have been placed into the interface.
(ii) It describes about the male and female connection at the terminal.
(iii) It describes the data terminator connection at the interface end.
- Electrical characteristic – These characteristics deal with changes in voltage levels and the timing at which these changes are happening. It is very critical that the DCE as well as DTE should use the similar voltage levels. The reason for this is that they should be able to access the same meaning for each voltage levels and the timing of changes in it. Then only a successful data transaction can happen. Or else, it will provide garbled data to the end user.
- Functional characteristics – These characteristics deals with the functions which are processed by the circuits (for data and flags transaction) as per their defined task for them. There are various tasks performed by the circuits such as data control, flag control, timing control and voltage level controls.
- Procedural characteristics – These characteristics indicate the succession of procedures for the successful transmission of data as per their functional characteristics.