On 7/19/10, Liam Proven <lproven at gmail.com> wrote: I use serial ports every week. It may be hateful 1960s nonsense, but if you know how it works, presuming you have the ability to control all the parameters of one end of a connection (software-controlled params, jumpers, straps, solder bumps, etc), you can still take something made in 1968 and attach it to something made in 2008. One recent case in point - After a couple of nights studying the schematics and the present state of the wiring (they mostly matched, after a fashion) of a 1970s Bridgeport Series II CNC mill (that has an embedded LSI-11 CPU!), I was able to build a round-8-pin-connector to DE-9 serial cable and interface the Bridgeport to a modern Dell that was also being used to drive a Shopbot. ?One thing relevant to this discussion about it was that we struggled with verifying that it worked when we tried to talk to it via a handy Thinkpad with a USB serial adapter (communication worked from the Bridgeport, but not to it). ?On a hunch, once we located a 6' extender cable, it worked on the Dell the first try. ?I'm reasonably certain the voltages on the USB serial adapter were out of spec for "true" RS-232 - the Bridgeport uses 1488s and 1489s, not modernish MAX232 drivers or other wiildly-forgiving line drivers/recievers. So for wiring up a passive cable, I was able to breathe life into a 30+ year old three ton machine. ?I was possible because I had a machine with a proper RS-232 port that stepped in where a machine that only had USB failed. Mac-designed things, sure, but Apple didn't make it easy to talk to the world full of "standard" serial devices (of which there were *lots* in the 1980s). Exactly. ?Around the time the Mac switched from DE-9s to DIN8s, I was in the business of manufacturing serial interfaces for DEC hosts. ?I worked with sync and async RS-232 cables and ports and drivers and application code every day. ?I still found it to be a pain to get the right arrangement to hook a Mac up to some foreign device. ?It got easier later when you could just buy a suitable cable off the shelf, but for a time, it was difficult. I really do not like USB. ?It takes hundreds of cycles and more to move a simple message, it's a host-based, not bi-directional design, and it's only available on somewhat newish kit. The host-based aspect of it is probably my biggest peeve - with a serial port, it's just TxD, RxD and perhaps some handshaking lines (more likely in the past, but sometimes supported in recent products). ?What that means to me is that I can buy a device that might be intended as a client (a Palm Pilot, to give a specific and handy example) and by dropping an app on it, turn what was manufactured to be a "receptive" device into an "active" device - such as use it as a VT100 replacement for configuring Cisco routers (boy my boss's eyes bugged out when I pulled a Palm out of my pocket, clicked in a serial cable and fixed something in seconds instead of leaving the room, retrieving a laptop, setting it up, etc., etc.) A USB-equipped Palm is meant to be addressed as a 'peripheral' and cannot be a 'host' - that limits its usefulness to me. I will agree with you there. ?Just last night, I was helping a friend with a dying LaCie drive on a Macbook and I was happy we had a Firewire 800 cable that walked into the door at the right moment - it turned a 55 hour copy job via USB into a 31 hour copy job (dd to a container file - hopefully there's enough left of the old drive to extract enough files from to make the exercise worthwhile). It has some advantages - power for light-duty peripherals is great, simple connectors is great, not having to worry about DCE and DTE orientation is handy. ?It's great for mice and keyboards, sure, but I'm less convinced about higher-bandwidth uses. And lest you think this is all some sort of neo-luddite rant, I've built and programmed USB-based peripherals like the USB4LCD. ?I participate (occasionally in recent years) on the libusb developers' mailing list. ?I've written user-mode USB drivers with libusb. ?I've debugged USB command packets and initialization code. ?I'm using a USB mouse right now. ?USB still drives me nuts. I'm hardly advocating the death of USB (though I don't think I'd shed a lone tear over it). ?What disappoints me is the loss of a "real" serial port on portable hardware (starting with old Macbooks, but now across the Intel world as well) and the massive overhead that comes with using a "USB serial port" (like the well-documented problems that Makerbot folks have with FTDI driver issues - things work better when you don't have a USB physical layer between your application code and your Makerbot, but few people run that way, in part because for many bot owners, their Netbooks or Macbooks or whatever have any sort of way to talk to the outside world except WiFi, Ethernet or USB). I also do a lot with microcontrollers, MCS51-family and Atmel AVR, mostly. ?You _can_ make an 8MHz Atmel do USB in software (cf USB4LCD), but it's a whole lot easier to tell that same chip that there's someone connected on its UART and speaking async at 9600 8N1 - you get lots more of your ROM available for application code, and you can attach that MCU to a much larger field of devices with a simple serial port. -ethan P.S. - I know USB is "consumer-friendly" and I know I fall far, far outside the definition of a "consumer", but that doesn't change the fact that ubiquitous RS-232 ports make my life easier and USB comes with a bag of hassles.

P.S. - I know USB is "consumer-friendly" and I know I fall far, far outside the definition of a "consumer", but that doesn't change the fact that ubiquitous RS-232 ports make my life easier and USB comes with a bag of hassles.

On 7/19/10, Liam Proven <lproven at gmail.com> wrote: I use serial ports every week.

It may be hateful 1960s nonsense, but if you know how it works, presuming you have the ability to control all the parameters of one end of a connection (software-controlled params, jumpers, straps, solder bumps, etc), you can still take something made in 1968 and attach it to something made in 2008.

Mac-designed things, sure, but Apple didn't make it easy to talk to the world full of "standard" serial devices (of which there were *lots* in the 1980s).

I really do not like USB. It takes hundreds of cycles and more to move a simple message, it's a host-based, not bi-directional design, and it's only available on somewhat newish kit.

The host-based aspect of it is probably my biggest peeve - with a serial port, it's just TxD, RxD and perhaps some handshaking lines (more likely in the past, but sometimes supported in recent products). What that means to me is that I can buy a device that might be intended as a client (a Palm Pilot, to give a specific and handy example) and by dropping an app on it, turn what was manufactured to be a "receptive" device into an "active" device - such as use it as a VT100 replacement for configuring Cisco routers (boy my boss's eyes bugged out when I pulled a Palm out of my pocket, clicked in a serial cable and fixed something in seconds instead of leaving the room, retrieving a laptop, setting it up, etc., etc.)

A USB-equipped Palm is meant to be addressed as a 'peripheral' and cannot be a 'host' - that limits its usefulness to me.

It has some advantages - power for light-duty peripherals is great, simple connectors is great, not having to worry about DCE and DTE orientation is handy. It's great for mice and keyboards, sure, but I'm less convinced about higher-bandwidth uses.

I really do not like USB.

It takes hundreds of cycles and more to move a simple message, it's a host-based, not bi-directional design, and it's only available on somewhat newish kit.