Interface a shared transition point between two or more functional units (device, PC, etc.) defined by common characteristics of physical interconnections, signal characteristics, and functional characteristics of interconnection circuits.
Protocol is a standardized set of rules for data transmission over a communication interface.
The communication interfaces used in the industry can be of two types:
Point-to-Point. There is only one transmitter and one receiver in the network; the data is transferred only in one direction per signal line.
Point-to-Multipoint. There is one transmitter and several receivers in the network; the data is transferred only in one direction per signal line.
The main characteristic of any communication interface is its baud rate. This rate determines the number of bits transmitted via a line per second (bit/s, Mbit/s, etc.). Usually, the baud rate consists of "payload" and "overhead". The overhead typically includes the packet format or protocol frame: source/destination bits, error checking bits, control bits, etc. The payload is the net data rate or the effective data rate. The payload varies depending on the particular interface and protocol and can be from 30% to 90% of the baud rate. This must be taken into account.
Interfaces and protocols used in akYtec devices:
| Interface | Type | Baud rate | Line length | Protocol* |
|---|---|---|---|---|
| RS485 | Point-to-Multipoint (up to 32 devices) | standard 115200 bps | max. 1200 m (without repeater) | akYtecModbus ASCIIModbus RTU |
| RS232 | Point-to-Point | max. 3 m | ||
| Ethernet 10/100 base T (twisted pair) | Point-to-Point | 10 Mbps / 100 Mbps | max. 100 m | Modbus TCP |
| USB 1.1 | Point-to-Point | 12 Mbps | max. 3 m | Mass Storage DeviceCDC Device |
| USB 2.0 | Point-to-Point | up to 480 Mbps | ||
| *depends on the device | ||||
Device compatibility
Device compatibility is the capability of devices to exchange data with each other. Each device participating in the data exchange must be equipped with a specific interface and support a specific protocol. Nevertheless, even in this case, the ability of exchange data is not always possible because one device may not be able to send the information that the other is supposed to receive. The question, therefore, lies in what to do if the devices support the same data type but have different interfaces and/or support different protocols. It is necessary to use interface adapters or protocol translation gateways.
Interface adaptera device with two or more interfaces that transfers the data from one interface to another. However, information transmission is carried out without its conversion. This means that the devices connected via an interface adapter should support the same protocols.
Protocol transmission gateway (or protocol converter) is a device that converts the data from one protocol to the other. In addition, a protocol converter can also serve as an interface adapter. In contrast to an interface adapter, however, the protocol converter must be configured for which data via which protocols is to be transmitted in the communication network.
Read more information in our post 'Interfaces and protocols used in akYtec products – Part 2'.