DTE vs DCE
In the world of networking, there are a lot of ways to connect devices, and even with newer equipment, old formats and techniques still come into play. It’s easy to think that things like fiber optics and Ethernet are on the new end of things — and the latest versions of each are certainly new. But, older forms of communication are still a big part of modern networking.
As an example, serial connections are still everywhere. They directly connect devices, but those serial connections often exist within a larger network, and it’s important to understand their role in everything.
The best way to gain that understanding is with a quick review of DTE and DCE.
What Is DTE?
Data Terminal Equipment (DTE) is any equipment that can serve as the source or destination for binary digital data. That’s a pretty wide category as many endpoint devices can fit this mold. More often than not, computers, terminals, and printers make up the equipment that is labeled as DTE.
More specifically, DTE refers to equipment that serves the terminal role in a connection. Such devices display user information, store user data, or generate user data. These are the devices a user will directly interact with in a connection.
What Is DCE?
Data Circuit Terminating Equipment (DCE) is a category that describes any unit that transmits or receives data through a network. These signals can be analog or digital. DCE can gain access to a system over telecommunication lines.
If DTE refers to endpoint or user equipment, then DCE refers to devices that connect directly to DTE.
Most commonly, modems and multiplexers make up the devices that you would classify as DCE.
Another way to understand DCE and DTE is by looking at the international standards. Most often, DCE and DTE communicate via the RS-232 standard. Other standards that apply to DCE and DTE include the Federal Standard 1037C and the MIL-STD-188.
RS-232 was created in the 1960s to regulate serial communications, and it is still used today to standardize signals between DCE and DTE.
DTE vs DCE
Seeing as how the standards are used for both types of equipment, the best way to consider DTE and DCE is through a review of how they work together. Communication from one typically involves the other, and that is because they are interdependent.
In a serial connection, one device usually provides clocking for the other connected device. As such, DTE will search for clocking along the serial connection, and DCE will provide that clocking.
Consider a simple example. A computer terminal tries to connect to the internet via a modem. The modem and the computer are connected together with a serial connection that conforms to RS-232. When the computer tries to connect, it has to communicate directly with the modem.
In this connection, the modem will provide clocking and direct communication. The computer will provide the user data necessary for the interaction. The two work together to send and receive information as needed.
That is the essence of DTE and DCE. They form opposite ends of conforming serial connections.
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