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On 19-Mar-2004, Meindert Sprang lamented the demise of serial ports on comp.arch.embedded:
Why? What exactly is wrong with a simple, cheap serial port? It's only the fault of the current game-driven PC industry that serial ports become obsolete on mainstream PC's. I don't see any real technical reason why serial ports should disappear.
Ulf Samuelsson replied with a list of advantages of USB:
RS-232 cables are not easy to use for the average PC user.How much time have you spent trying to get RS-232 to work, and found out the cable was not suitable. A user simply cannot make those mistakes with USB. RS-232 means phones calls to the vendor. I do not know how many phone calls a user have to make for the vendor to lose money - they hate that
- DTE + DCE
- Male /Female connector.
- Cables with strange internal coupling
- Home made cables....
RS-232 connectors are more expensive than USB connectors.
RS-232 is limited to 115 kBAUD in std PC configurations. This is a pain when you have requirement for faster speed.
Each RS-232 port needs I/O and Interrupt. You do not have many interrupts on a PC.Do you need more?
Call me an old fashioned curmudgeon, but I'm not convinced that USB is that much better. I replied:
With suitable cables and/or adapters, you could plug together almost any pair of EIA-232 devices. With USB that's generally not possible. For example, I used to have a PDA, a modem, and a computer all with serial ports. I could attach the PDA to the computers, or the modem to the computer, or the PDA to the modem.My new PDA, modem, and computer have USB ports instead of EIA-232 ports. Now I can connect my modem to my computer, or my PDA to my computer, but if I want to connect my modem to my PDA, I'm just s*&$-outa-luck. This is reportedly "progress".
"USB On-the-Go" is supposed to address this, but it seems quite unlikely that it will ever have the degree of flexibility that EIA-232 connections had.
USB vs. EIA-232 is like a GUI vs. a command line. It makes simple things easy, and more complicated things impossible.
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Last updated 22-Mar-2004
Copyright 2004 Eric Smith