RS-232 vs. Ethernet


Thread Starter


What are the advantages of these two as far as:
- robustness?
- speed?

Where can I learn more about this?
Ethernet is much, much faster than RS-232. The robustness of either depends on how well the hardware and software were built.

RS-232 today is mainly found in applications where very low cost is more important than performance. It has almost completely disappeared outside of industrial and certain other specialised applications.

Ethernet - Fast. Transformer isolated. More capable protocols, but in industry plagued by many of the industrial application protocols being secret/proprietary. Most of the protocols in common use outside of industry are open.

RS-232 - Slow. Non-isolated (opto-isolated hardware is available, but rare). Many, many simple protocols are in use, but they are often publicly documented.

Which is best depends on what they are being used for.
- robustness?
Ethernet has a better shielding against magnetic disturbances (also optical cables possible). RS-232 has not. RS-232 lines have a limted length only. If you have longer distances you must use modems.

- speed?
Ethernet is much faster than RS-232 but RS-232 gives you a guaranteed speed, where Ethernet provides a best effort speed depending on the current network traffic. (As long as we do not speak about quality of service (QoS), which is now also available on Ethernet.)

RS-232 is point to point, where Ethernet can interconnect any number of boxes.

- Where can I learn more about this?
You will have to read something about the ISO/OSI model.

RS-232 is a "Physical Layer" within the ISO/OSI model (not more).

Ethernet covers "Data Link Layer" AND "Physical Layer".

What we normally use is TCP/IP (software). This is:
- Transport Layer
- Network Layer
- Data Link Layer
- Physical Layer

We code TCP/IP on top of the Transport Layer using the socket interface.

The higher layers of ISO/OSI do not exist within TCP/IP. Instead the upper layers are within 1 piece of software. Example:
http: ftp: ssh: telnet: smtp: pop: imap: ntp:
... and much more.