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Will the Serial Console Ever Die?
simpz writes "Will the serial port as a console connection ever be displaced — especially for devices such as switches, routers, SAN boxes, etc.? In one sense it's a simple connection. But it is the only current port that, in order to use, you need to know about wiring / baud rates / parity, etc. It has non-standard pinouts. And it is becoming too slow to upload firmware to dead devices, as the firmware updates get larger. Also, the serial port is rapidly disappearing from new laptops — which is where you often really need it, in data centers. Centronics, PS/2, and current loop are mostly defunct. Is there any sign on the horizon of a USB console connection?"
I use one just fine with an old WACOM 12" tablet under linux, so while the port may be dead, we can still use serial software and hardware. There's no reason you can't use two $15 converters plus a null modem to run that old DOS-based serial telecom program (ah, telix ... thanks for the memories).
Most of the newer switches, routers, multiplexers and any other device with a serial port for a terminal interface I've had the pleasure of configuring had a web interface. I'd say that's the direction manufacturers are headed and is the next logical step.
~Mike (Titan_X)
He means on desktops, laptops, servers, and shit like that. Other than cisco routers and switches, you can't really fine hardware that has a serial port on it. But all routers and switches are still manufactured with serial...
It calls out to you.
The great thing about a serial console is that it doesn't take long to figure it out. And you only need 3 wires to get there.
Another nice thing about it is that it's point-to-point, so you don't have to worry about your signals getting lost.
Heck, you can create a serial interface from discrete components if you're really into fun.
So use your serial console for what it's intended to be used for: emergencies and initial configurations.
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I upload firmware and program various devices at work via USB or TCP/IP - and it is great because the connections are fast. However, when something goes very wrong with the devices, the RS232 port always works. Also, being able to get serial data just by listening to a couple pins is far easier than trying to deal with USB connections/drivers you have no clue about.
When it comes down to it, serial works, its easy and it's a life saver.
It will never die. It will be around forever. Technicians, thousands of years from now will have to interface with wireless psychic rs232 adapters so as to configure their Cisco hyperdrives.
As an embedded device engineer, I love good old UARTs. They are very small cores to add to an FPGA design, simple to write a driver for, and fast enough for most simple debug applications.
Trying that with a USB core is not an easy prospect. And they arent *that* slow. The free UARTlite IP core from Xilinx can run up to 921,600.. plenty fast for most things embedded...
It will exist as long as it is useful. Right now, people are still finding it useful, therefore it still exists. You still see ISA ports around sometimes.
Qxe4
"Other than cisco routers and switches, you can't really fine hardware that has a serial port on it."
Every piece of DC-worthy gear I've touched has had serial.
Of course, most stuff either comes with serial *and* ethernet, or allows one to hop in via serial and set up a web-based interface, but serial is always there.
I work for a small electronics manufacturing company, http://www.westmountainradio.com/
and we make a number of devices that use the serial port. In recent years, we had to start including USB-serial adapters with every device for the very reason mentioned: Many newer computers simply do not have RS232 ports anymore.
The RS232 port is a very convenient way to connect with a number of peripheral devices that don't need much bandwidth. In most cases, 9600 BPS is plenty. You also have the "handshake" lines which can be used to toggle an external device on or off. We use it to drive an LED and an opto-isolator to key a ham radio transmitter, among other things.
As long as there are low-bandwidth, human-interface devices, there will still be SOME use and purpose for the RS232 port.
Willie...
When it comes to managing important network switches, no, they aren't gone.
When an important switch fails for some reason, how do you contact it to see if it's recoverable remotely? (i.e. when your network admin has to manage switches that are located at remote satellite offices)
Out-of-band management addresses this limitation by employing a management channel that is physically isolated from the data channel.
I still design lots of equipment with serial interfaces inside. It is much easier to connect to a low-end microcontroller which may barely have even a single UART. And even for a higher-end processor, it's so much easier to build the interface. Developing a USB interface requires a pretty detailed understanding of USB - selecting endpoints, which transfer protocol to use, etc - so there's a big software investment and often a significant additional hardware investment to implement a USB interface. Serial is often damn close to free, so easy that it's a no-brainer to put in. And for ethernet devices like switches I can't imagine why anyone would want to bother with a USB interface when you already have 8/16/48 copies of an ethernet interface available, just plop down yet another copy of the ethernet PHY design and make that your console interface.
Point is - serial's EASY to give you, so you're gonna keep getting it for a while.
Just my $0.55 (US inflation, 1774-2008, for $0.02)
I actually posted an Ask-Slashdot about running a headless Linux Box that didn't have any serial ports... my question was about what happened in the 5% of cases where I couldn't SSH to the box (like if a kernel upgrade goes south). The basic answer was that I still needed a serial terminal. Oh, I know that USB can be used as a substitute, but the problem was that USB required a booted & functional kernel with a working USB stack to emulate the serial line. I recently saw a similar discussion in comments about how bad the old-school serial terminal code that is still in the Linux kernel is. Many people incorrectly thought the poster was saying that Linux shouldn't have a command line interface, which was completely wrong. The poster instead raised the (excellent) point that complicated and buggy software emulating long-obsolete device interfaces may not be good for the Kernel (CLI is NOT the same as a terminal interface).
Are there damn good reasons why RS-232 serial ports should be dropped from modern hardware? Hell yes, not the least of which is a 3-15 volt swing signalling protocol is an invitation to fry the low-voltage electronics on modern systems. However, the CONCEPT of having a box that does not require any type of graphics, or even a working network interface, is still very useful. So... what are the better technologies to accomplish the same goal without having to rely on antiquated hardware implementations?
AntiFA: An abbreviation for Anti First Amendment.
Unfortunately yes. In my workplace we still use floppy disks and other legacy devices because other institutions also still use them.
Processes and systems that were setup 20 years ago still exist and when there is a system setup to handle something across an industry, in the example I'm thinking of its banking related, to get that changed across every company, institution and outlet take not only large amount of capital invest in the new hardware and software, but first agreement of the new standard, and then training after everything is done and then usually also changing large amounts of code that have been setup in each company.
Just because we in IT can see better ways to do things, doesn't mean that management can have the foresight to actually implement it and see it through. And usually they have a point, by the time we have everything implemented and up and running, there could/would be a better way of doing it again!
There is no -1 disagree
Serial is cheap, simple, works really well, and you can hook up 15+ year old equipment to it with no problem.
Is it slow? Not really, but firmware updates should be through TFTP or HTTP by now anyways for larger files.
Complicated wiring? RX-TX TX-RX, common ground.
Also RS-232 has many brothers and sisters like:
RS-422 (a high-speed system similar to RS-232 but with differential signaling)
RS-423 (a high-speed system similar to RS-422 but with unbalanced signaling)
RS-449 (a functional and mechanical interface that used RS-422 and RS-423 signals - it never caught on like RS-232 and was withdrawn by the EIA)
RS-485 (a descendant of RS-422 that can be used as a bus in multidrop configurations)
On the USB console: yeah, you can have a USB console. Most like there will be a FTDI chip, which will make your USB into a serial connection. Want an example? Arduino.....
By the way, the post is kinda mis-worded.... USB is a serial bus, so a USB console is technically a SERIAL console :)
Have you any idea how insecure it is to access the bios via ethernet? It's hard enough keeping things secured when a box is internet connected, but allowing people to set the bios options and early boot process stuff via ethernet is absolutely insane and an incredibly warm invitation to crackers. And if it doesn't allow you to do that then it's more or less useless as a replacement for a serial console anyways.
Yes, they filter dust in my desktop machines.
Fuck systemd. Fuck Redhat. Fuck Soylent, too. Wait, scratch the last one.
Screw that. I do programming for embedded systems and serial is absolutely essential. Even the simplest bootloader supports standard serial. Hell, you can write an implementation of rs232 in an fpga in about 20 minutes. Its ubiquitous because requires no real software to make it work...and when you have barely any software working on a system, that uart can be the difference between hours and weeks of debugging.
I work in the offshore survey industry (oil/gas industry), and 95% of products to date still come with serial ports. They are critical for our purposes, and onboard com ports are a must for timing critical jobs such as multibeam bathymetric surveys.
Current project im working on we are using Moxa multiport serial boards w/ 32 serial ports on this pc with around 25 currently inuse for IO. (Historically used Digi boards but they were awful for timing (relatively!), 30ms delay compared to the near 0ms on the Moxa units.)
Simple to use, easily available, and cheap. Almost all the devices I work with use standard parity/stop bits etc, just varying baud rates, which is easy enough to remember.
like a fox..
I attended its funeral yesterday. It was an open-casket ceremony, and people just couldn't seem to resist fingering the deceased. Sadly it didn't respond.
Wait till you learn about DLC
Is there any sign on the horizon of a USB console connection?
There is no standard USB device class for serial adapters. There is communications device class, but it is huge and doesn't really help. So FTDI and Cygnal and others have to write their own drivers for tens of OSes and architectures. If you walk up to a device with a laptop and a USB cable, chances are that your laptop doesn't have a proper driver. To make things worse, many USB-Serial adapters have to use their own VID/PID/REV identifiers, and that makes it even harder to recognize the device. Class-compliant devices would "just work" like a USB drive does, or a mouse.
There is also no standard API in OSes to talk to *modern* serial devices. USB serial devices are emulated into a virtual COM port.
I understand what you are saying: RS232 ports suck for any number of reasons.
But there are a few why it is still often used.
First, it has been ubiquitous for 20 to 30 years. When I started my first development job in 1982 - everything talked to everything else via RS-232. Back then 9600 baud was considered fast. At 8 bits per character with no parity and one stop bit, 9600 baud could paint a screen with characters in one second. Yes, we thought that was fast. Things got better as baud rates improved - but RS-232 remained everywhere - it was the one constant universal interface. Even though it is incredible antiqued, it is still in many PCs.
Second, RS-232 (and its many cousins like RS-422) are very, very easy to use in software. The simplest I/O can be done in a few lines of code. Its easy to put RS-232 code right in firmware. This makes it easy to write bootstrapers, boot consoles, debug consoles etc.
USB would be a poor choice for a replacement. The reason is that it isnt peer to peer - it is a master/slave architecture. There is always one master -usually a PC, and one or more slaves (keyboards, mice, printers, scanners, cable modems, disk drives, storage keys, cameras etc).
It requires a special cable to make to client USB devices talk to each other. This cable has a small do-dad that looks like a master to both ends. This works ok, but it requires special knowledge of this USB end point to work correctly. Note, Windows began to support this in Vista for migration. Its called Windows Easy Transfer/a>.. There is a version for XP too (downloadable/a>). It actually works very well, but the cables were not cheap. Note that the cables really are not cables - but a dual-headed master USB controller with two ports - it just looks like a cable with a lump in the middle - Belkin sells one for $40.
LLike a few other posters have said - USB is much more complex to use in software than simple RS-232. Ive written code for it and I find it more complex than Ethernet at the MAC level.
I think Ethernet is the real replacement. A little TFT or Telnet server / client is really trivial to write. This can (and often has been done) in firmware. For example, most (all?) home Ethernet and wireless routers dont have a serial port. Their management is over Ethernet - works great.
-Foredecker
Jibe!
Well, I disagree about that being the only place. Serial ports are absolutely huge in the embedded world. A large number of consumer devices also use serial internally, and maybe convert to USB right at the edge of the box.
Networking brings up an interesting point. I actually prefer to add Ethernet to an embedded design over USB. It's actually easier, if you can believe that bull****. It's also massively more flexible and quite a bit faster.
Many TCP/IP stacks can be ported to a new platform by simply implementing a read, a write, and a status function to talk to your specific MAC.
USB is usually a horrible kludge taking some vendor's usb-to-serial or mass-storage example code and hacking the crap out of it until it works. The USB module registers are so different from vendor to vendor, etc.
At the PC level, it's different. There are some standards there. Even there, it usually takes custom device driver work to get a new device working... something that Microsoft should be totally ashamed about. They really should have provided something like libusb on Linux.
To summarize, USB is a horrible horrible bus for the thousands of smaller embeddded shops out there. It requires dealing with incredibly poor quality vendor example code, and worst of all you have to find someone who can write you a Windows device driver. Well... unless you're lucky enough to know how to do that yourself. I can, but it's such a pain in the ass that I'd much rather use Ethernet... which doesn't require a stupid driver on every OS you want to use it with.
RS232 is easy to program. If it's a switch without OS or some other embedded device, RS232 is the easiest and fastest way.
Sure on the PC side there are the problems of baud, parity and so on. Thing is on the device side you can get a working bidi buffered transmission within 30 lines of assembler (100-200 if you have no UART and need to push each bit yourself). Writing equivalent of "hello world" over USB becomes kilobytes. And if you go into a web interface, you quickly lose enthusiasm as you realize on top of CGI you need to write the web server, the TCP stack, the IP stack, and if you're unlucky, the Ethernet protocol stack (in VHDL) as well.
On top of that, a thousand things can go wrong in writing USB or Ethernet or whatever. RS232 is rugged, fault-proof, it works from moment zero. You will be able to communicate with bootloader which has no idea what ethernet is, you will be able to diagnose faults when 90% of essential peripherials are fried, and if the cable goes loose, just move it around a bit and the connection will be back, no timeouts, no disconnects, no "intelligence" to get in your way.
And if you open various devices that use USB instead of serial, you will find a neat little FDDI, Profilic or such chip connected to the USB interface. The devices really connect over RS232. They just have the "RS232 over USB dongle" built in.
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My phone (Palm Pre) can even pull bootloader code over USB, so even if the boot flash gets hosed, it can recover via USB.
Serial shouldn't be needed outside of microprocessor development these days... that it is is sad.
Sure, a board may cost $0.50 more to manufacture... yea, stop penny-fraction-pinching you bastards!
For large sets, this will be our guide even unto death, for the LORD will work for each type of data it is applied to...
I can't speak to switch access, but the serial port is paramount in the medical instrumentation field. Virtually all interfaces are serial. Need to hook up a CBC machine? Cobas? Vitek? Serial!
Most machine shops -- their equipment is serial. Sending cut information to the lathe? Serial.
Guess what every SAC box has strapped to the back of the equipment rack - a US Robotics full-size (about 12"x7"x1") Courier modem!
Damned if I know where they're getting them from - but there they are...
Been there, done that, paid for the T-shirt
and didn't get it
An awesome point that can't be overstated. Well, probably not anyway. There are modems, converters, terminal servers and several other ways to use a serial port on important hardware. Out of band management is one of the best reasons for ever using it. The dial up modem as fall back to access servers has not been replaced yet. I imagine that there are a few reading these posts that know serial backup saved their bacon more than once.
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With the increasing complexity of network devices - switches, routers, load-balancers, firewalls, the expectancy of a functional terminal console puts a good design constraint on system developers. If they have to provide the ability within a 80x24 terminal funtionality to configure, operate and maintain a such a device it is a good thing. A good management is useful in providing an overview of the configuration and helps provide linkage to the management of components.
A serial terminal console is good because:-
* It enforces the designer to limit the presentation of management information to the 80x24 screen (possibly using pages), and often with a 9600bps data rate. My view is if they can't do it properly in a console they have not though well enough about management. Too often GUIs for management tend to hide important configuration parameters away.
* A terminal console allows easy copy-and-paste and script munging of configurations to ensure consistent deployment. GUIs don't allow such duplication of configurations very well.
* It allows simple out of band management through the use of a terminal server connecting multiple consoles. Such a simple management connection provides am always available management window in a network down situation. (Assuming this is deployed properly). You can also manage the risk well if management can ONLY be done by serial (preventing the management network inadvertently being connected to a production network.
* While standarardisation of the physical port (male or female DB9 or RJ45) and host type (DTE or DCE) and even hardware handshaking is right royal pain. At least it is usual possible to determine it after a minimum number of tries. But essential it is pretty straightforward to implement.
* While a USB connection sounds good, I would only prefer it if it was guaranteed to be a zero driver installation.
You young whippersnapers and your newfangled serial consoles.
Back when men were men, this is what a manly console looked like; http://www.columbia.edu/acis/history/360-91-panel.jpg
Ian Ameline
We have about 20,000 servers, plus switches, routers, firewalls, and a whole pile of other gear that all has serial access through out of band management systems; ALL of them have serial ports natively. Why? It's simple (it is NOT non-standard, RS-232 is quite established), basic management often doesn't require anything more, and when the system goes completely tits-up it often gives a method of recovery not otherwise available without having to physically be in front of it (hard to do with equipment around the world).
Just because you can't type http://accessmyshit does not mean it isn't still very useful in the real world, particularly at large scale enterprise-grade data centers.
Then you are looking at old catalogs my friend.... no, serial is not included on every piece of hardware.
No, that little RJ45-looking jack labeled 'Console' on most newer Cisco and HP gear is actually for a serial to RJ45 cable...
There's no place like
We buy those all the time for OOB redundancy. 56k US Robotics modems run about $300 now though. Pretty funny as I used to have boxes of the old 28.8 and 33.6 ones from when I shutdown a modem bank that I recycled. Now I get to put in purchase orders for 10 modems at a total of 3k. Always makes me laugh.
I'd hope these days a big honking server mobo would at least support booting from USB key.
Most of them do--but you have to realize that it took Microsoft until 2008 to release a server OS that doesn't require floppies to load RAID drivers.
There's no place like
^^^ Amen. For anyone into embedded electronics (including robots), real honest-to-god non-USB-bridged serial ports are pretty much the only port left on a modern PC (or at least a decent thirdparty motherboard in the form of an IDC header) that neither Windows nor Java can fuck up.
Other than cisco routers and switches
Are you serious? The only examples anyone on Slashdot can find seem to be routers and switches? The reasons RS232 isn't going away is because an awful lot of industrial automation equipment (large and small-scale) still uses it. Why? Because a) all of the existing industrial automation equipment uses it, so new equipment is designed to be compatible with existing interface and control systems, b) it has proven itself to be incredibly reliable over the years, c) it's cheap (in terms of money, but also in terms of the amount of supporting hardware required). Also, while it may not be fast enough to transfer huge firmware images or run high-bandwidth stuff like video over, it's fast enough for what it's used for. If a firmware update takes 5min to do on a $100,000 piece of factory equipment, so what? The company probably spent a month planning for the upgrade, and will spend a week testing it after the update to make sure it still meets performance and safety requirements before re-deploying it anyways. There are billions of dollars invested in RS-232 by some highly conservative companies that don't change things on a whim, when a complication arising from an unnecessary change could cause 5-figure-per-minute damages or loss of life.
Why is RS-232 still around? Because it ain't broke, and it don't need fixin'!
Outside of Real Serious Stuff(if your job involves oil rigs, SCADA, legacy devices that Google has never heard of this probably means you), I strongly suspect that "serial" in the sense of "DE-9 or DB-25 connector that won't freak out when exposed to the full +/- 12(or even a touch more in some cases) volts that serial used when men were men and cable runs were long" is not so long for this world, outside of a few legacy niches.
On the other hand, "serial" in the sense of "a few pins carrying something that looks like rs-232 at whatever voltage this device's logic runs at" or "device has a USB connector; but that just means that they slapped an FTDI or Prolific chip on a serial design" will be more or less immortal. Even in high volume consumer devices, where it isn't supposed to be user accessible, you can generally find a logic-level serial connection somewhere, though it may not be labeled or have any sort of connector soldered in. It costs almost nothing and can save you from having to JTAG your way out of (most) of your mistakes. When designed to be accessible, it is ideal for dealing with initial configuration for devices that communicate primarily over ethernet.
Not much really - it only takes a very minimal stack to do simple things like TFTP or Telnet. Back in the mid 90's We used do to do this on '186 class stems in a few k of code. Its also easy to do a very simple low level UDP based thing - that that would be a bit proprietary.
I agree that serial ports are useful. What I'm suggesting is that the best alternative is Ethernet, not USB.
Jibe!
From a device manufacturer's point of view, RS232 is free to implement. No special drivers are required on the host.
Now, for USB, you have to either pony up $2000 PER YEAR to the USB implementers forum to get your own VID/PID and distribute a driver to your customers (and deal with the resulting customer service issues) or add a chip from FTDI (or similar) and piggyback on their VID/PID but then ask your customers to download and install a generic driver that does not specifically identify your hardware.
Gimme RS232 any day.
I'd hope these days a big honking server mobo would at least support booting from USB key.
Most of them do--but you have to realize that it took Microsoft until 2008 to release a server OS that doesn't require floppies to load RAID drivers.
Then again, it's hard to take anyone seriously that uses Windows in a server role.
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. . . but it's that "because I can" that often makes sysadmins who are familiar with this "antiquated" technology extremely valuable.
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Not all hardware has to be thrown into garbage just because it's old.
This machine has 11 UARTs on it, 4 of them are RS-422, the rest are normal 232.
I've got a couple 232 lines to other puters in this room, and a router.
RS-422 goes down to the basement, and controls the machines down there, ethernet or not.
There is a getty running on one, in case I get too drunk and smash the monitor.
I use the remainder for connecting to my microcontroller projects and programmers, etc.
You can run it on *ancient* hardware, with no resources. It's incredibly useful for debugging microcontroller programs.
Things that only have 128bytes of RAM, and a few k of program rom...
You can hook it up to a 40 year old TTY and it will work.
You can haul a dumb terminal out from a cave and it will work.
You can short every pin of the serial port together, leave it there for a decade, come back, and the bloody thing will still work.
I'm a rather miserable programmer, and serial is a bloody cakewalk to interface to. USB, on the other hand, isn't quite as simple.
And it's a *standard*. Man I love things that are standardized.
Sent from my PDP-11
Funny, I just walked around my ICU and everything is connected via ethernet. Monitors (philips), ventilators (dragers) and of course the computers (windows). Even the dialysis (prismaflex) machines hook via ethernet.
The ultrasound has an ethernet cable attached as do the image intensifiers. The biochem lab also works over TCP.
Certainly nothing major in the hospital that I work in uses serial connections.
Maybe the older equipment used to use serial but given the amount of data shuttled around I don't think it would be feasible so use serial. Of course I can only draw experience from where I work, other hospitals may be different.
Charles
I've been developing for the Atmel ATSAM3U chip, which uses the ARM Cortex-M3 core. Its development board has serial ports, but I can reprogram the chip entirely, from full eraase, with just the built-in USB port.
When erased, the chip boots off an internal ROM. That ROM, if yo have a 12 MHz crystal hooked up, will activate the USB 2.0 Device port and make it look like a serial dongle. You talk to the thing via /dev/ttyUSB0 and download the program top flash through it. As a final step, you run a couple commands on it to switch the booting over to Flash. And you're done. If you want to erase the chip, there's an ERASE pin you pull down for 200 ms or so, and it's erased.
The dev board adds another twist to it. It has an onboard NAND Flash chip, which uses the built-in ECC unit on the SAM3U. If the development board is running the demo code, then that NAND Flash will show up as a USB thumb drive when you plug the board into your computer. So you can read and write the NAND Flash from your computer as if the ARM wasn't there. The board ships with its source code, binaries, and data sheets on that NAND Flash, just to prove its point.
This is where the future is going. RS-232/422/485 will become more and more niche oriented. Industrial apps that need more than 15 foot cables will still use serial ports.
But I doubt it'll always be a requirement for embedded work, I've found that using an FT232 USB-to-serial chip is the way to go in my embedded designs. It pretty much replaces the RS-232 transceiver chip, and doesn't need charge pump capacitors or funny voltages. You never need a null-modem adapter or gender changer. You never have to wonder what baud rate/parity/whatever is needed; just set that in the FT232's EEPROM. The chip hooks directly to TTL serial port pins that all microprocessors use. You can even choose if you want handshaking or not, and the FT232 can even drive activity LEDs for you. A USB Mini-B or Micro-B connector is far easier to find a home for than a DB-9. What's not to like?
I've been using serial ports for 25 years. I will NOT miss them.
Serial is essential! It's cheap, simple, lots of hardware support it, and there's minimal firmware support needed for it. If you've got 8K RAM and runs at 1MHz, you don't want to waste it on a bloated USB driver. Serial port works from an interrupt context, so you'll be able to use it many times where USB can not work (say your OS is busted and you need to debug it).
Serial port isn't used because we're Luddites, but because it works.
Now if things had standardized on external I2C or SPI ports, that could work. But USB is just bloatware in comparison.
This is especially true in low-frequency micros. Not only does USB require complicated software both on the chip and on the pc (not to mention the licensing issues), it uses a lot of cycles just processing the stream. With UART any jack-ass with a C compiler can write the next killer text-based rpg in no time.
Also to note, you can do cool things with serial. e.g. A BlueSMiRF device can sit on the outside of your serial device (just connect TX/RX and give it power), and it instantly transforms it to a Bluetooth signal. You can then read and write to serial via any computer with Bluetooth (pretty neat). Should mention this does break poorly-written timing sensitive serial applications like some bootloaders. But there you have it.
"Software is getting slower more rapidly than hardware becomes faster." -Wirth
Lets see - I'm building a UAV using RS-422 for fly-by-wire operation using a RTOS and embedded hardware. Do I want TCP/IP or USB buffers involved on servos that control its ability to stay in the air? I can only imagine getting a lecture from an engineer at Raytheon about keeping things simple.
I wonder if someone will make a joke about selling Toyota Motor Corp a USB accelerator control...
Penny-fraction-pinching? Sir, that figure you've mentioned is fifty pennies! Why, with those, I could buy...
...
...those are FIFTY WHOLE PENNIES, SIR, AND I INTEND TO KEEP THEM!
not much, just being forced to manually insert line breaks into my comment
It is most often sufficient to delete the Serial Port in the Device Manager and then run a scan for new hardware.
I don't no if you actually checked, but a RJ45 could also be serial. A lot of Cisco equipment for example has a RJ45-connector for speaking serial.
New things are always on the horizon
I think the DB-9 connector is a little big for what its doing though, I mean even a DB-15 monitor type connector is duplo size for 15 pins.
Maybe I just like Cisco to much, but it would be nice to have everyone just use the Cisco RJ-45 spec for serial connections, I hate when other router/switch vendors use RJ45 but the pins-outs are totally different so you have to find that special DB9 to RJ45 adapter for that 1 piece of gear, instead of using 1 of the Cisco adapters that you have laying everywhere.
Even if on the back of laptops they used RJ45 for serial and marked they would keep it around longer? the DB9 connector seems to big realistate wise to me I guess.
Then you could just use a regular RJ45 cable to connect between the 2, no need for some non-standard cable.
Also for those of you that use console servers allot, I still think the older Cisco access servers that many use for console servers now a days are better than any of the Linux server type solutions I have tried. The Cisco access devices supports telnet to each port, a real routing table that supports multiple gateways via static or even routing protocols like OSPF etc... also Tacacs+ auth if you need that.
Probably SPI, ISP or JTAG, of which only ISP is a RS-232 Serial Port and provides the fewest options.
(no PC stepping, no memory access , no register access, no offline programming)
"I was in love with a beautiful blonde once, dear. She drove me to drink. It's the one thing I am indebted to her for."
Would grandma be using a serial port in the first place?
Jackass.
FTDI chips have very reliable and freely available drivers for their ICS for Windows, Mac OS X and Linux. Their ICs are so easy to use that you don't even have to think about them, the work is already done on both the PC side and the uC side. You code as if both sides were using an actual serial connection, the FTDI chip does all the USB-serial work. They're really plug'n play.
Look carefully. Sure, most don't use DE9 as it is a huge connector, but they will have the pins required for RS-232 signalling. A popular choice is RJ-45 (with frustratingly varying pinouts, requiring multiple RJ45 to DB9 conversion cables for a heterogeneous environment). Some use a mechanically mini-usb port that is actually RS-232 (Nortel comes to mind). I've even seen some equipment that did RS-232 signalling over 3.5 MM jack. I've also seen a number of wacky one-off form factors, whatever they can do to save real-estate and at least get transmit, receive, and ground lines out (5 pins if hardware flow control is desired).
XML is like violence. If it doesn't solve the problem, use more.
Heh. Indeed. If grandma is standing in the MDF room cursing at a Cisco router with a laptop balanced on the back of a chair, she probably knows how to disable/enable a serial port in Device Manager
If a job's not worth doing, it's not worth doing right.
Yeah, I tried to put XP on my new machine a couple years ago. It couldn't see the RAID array, so I grabbed the driver CD and pressed (whatever) to load the driver.... and it said INSERT FLOPPY DISK! WTF?!? It might as well have said "Insert papyrus scroll"!
If a job's not worth doing, it's not worth doing right.
and all those cute baby blue cables you get when you buy cisco gear
Ugh. Thank God a recent HP Procurve purchase got me a pair of tactical black cables...
There's no place like