74

None of them will do anything you expect. At all. The green one is a USB to PS/2 converter, it is a wire converter rather than signal converter. It will only work if the device you plug into it can detect how it is connected and speak both languages. Your USB stick will not do that, a USB mouse might. The next is a PS/2 mouse to serial converter, again ...


64

In the command prompt use mode Used without parameters, mode displays all the controllable attributes of the CON (console) and the available COM devices (and LPT as well). Accepts /? switch for basic help: mode /?


62

You can send data/receive data over the serial port using a null modem cable, or adapter with a serial cable. However, odds are high that you dont have one. On top of that, you will need to install software (such as a very old version of Laplink) on the laptop in order to use it. Even if you do purchase the cable, floppy disk, and find and install the ...


31

That is a male serial connector. The big one is a female parallel connector. It used to be common to have both 25-pin serial ports (true RS-232 ports) and 25-pin parallel ports (smaller than the original Centronics parallel ports). The parallel ports were female, and the serial ports were male. This prevented accidentally connecting a cable to the wrong port....


28

I found a useful answer at How to clear or Reset COM port ? Click start → Run → type regedit and click OK button Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\COM Name Arbiter Now on the right panel, you can see the key ComDB. Right-click it and click modify In value Data section select all and delete reset to zero (0) Its 32 bytes with ...


23

To answer the "at what point does it stop working" part, it depends what is being converted. I personally have an old AT keyboard, into a AT/PS2 converter, which connects to a PS2/USB converter and connects into a USB KVM. That's two adapters in a row, or three if you count the KVM. Any number of extenders or joiners would work, up to the point where ...


15

See which UARTs where detected in /proc/tty/driver/serial. A line with uart:unknown means: nothing detected (and likely not existent). # cat /proc/tty/driver/serial serinfo:1.0 driver revision: 0: uart:16550A port:000003F8 irq:4 tx:0 rx:0 1: uart:16550A port:000002F8 irq:3 tx:111780 rx:1321 RTS|DTR|DSR 2: uart:unknown port:000003E8 irq:4 3: uart:unknown ...


14

Thanks for all the advice above. I wrote software to automatically clean up the Registry but though it did adjust the Hardware, Software, and Arbiter sections it did NOT remove the phantom COM port entries. Even a reboot with the "USB to 2Serial Port" device removed did not clean up the system properly. However, the instructions on this PDF did work ...


14

I know the question has been answered, but this is another method. In command prompt, use: chgport in windows Vista and up. Lists your ports and which device they are.


13

Is DB-25 port Serial or Parallel? A DB-25 connector could be serial port or parallel port or something else. A DB-25 connector is a generic connector. It is not exclusively used by just one interface (like HDMI or USB connectors are). On a modern PC, a DB-25 (especially a female connector) is typically associated with a parallel (aka LPT) port. On older ...


13

I think the best way to understand the serial communication is with special software( as you were planning). You need to sniff and monitor serial port ? And with windows 7 x64 support. Then try this soft - Eltima Serial Port Monitor: http://www.eltima.com/products/serial-port-monitor/ It can analyze and monitor all serial port activity in a system. Besides,...


13

In the command prompt use: C:\>wmic path Win32_SerialPort OR In PowerShell: PS> Get-WMIObject Win32_SerialPort OR PS> Get-WMIObject Win32_SerialPort | Select-Object Name,DeviceID,Description Hope this helps.


12

There is probably no real usage of the line, but a permission issue. quick and dirty way to test for me was to execute: ls -la /dev/ttyUSB0 sudo chmod 666 /dev/ttyUSB0 and retry cu. If it starts working, you need to take care of the respective udev file and the user permissions/groups. For my device it looked like this (being member in plugdev group): >...


11

It's pretty easy. Under Linux there are serial devices, redirection and netcat for that. On the server you can run a netcat process listening on a given tcp port with stdin and stdout redirected to/from the serial device like that: nc -l 9801 > /dev/ttyS0 < /dev/ttyS0 Where 9801 in this example is the tcp port to listen on. You can setup the serial ...


11

After much fiddling around, I finally figured out the right combination of things to use for a fully usable terminal. tl;dr: FTDI-based usb/serial adapter, terminal set to VT220 with flow control both ways, special settings in /etc/gettytab The details Hardware I got a new USB/Serial cable. This one has the FTDI, rather than the Prolific chipset. This is ...


10

The original serial had 3, 5 or even 7 pins, but only one to carry the data. The three pins serial worked like this: The extra pin for a common ground is needed so that the other computer knows what to compare the data signal with. The receive and transmit lines are crossed, so that data transmitted by computer 1 is received on the receive pin in computer ...


9

This tool WILL work if you are receiving the (Code 10) error. Despite all the comments about it not working on Windows 8/8.1, there is a simple way to make it work: Fake PL2303 – how to install on Windows 8.1


9

You are looking for a serial terminal server or console server. Many manufacturers make them such as Raritan, Lantronix, and Black box.


9

Are the start bit and the stop bit(s) optional in serial communication? No. Presuming RS232 (or a TTL variant thereof). Consider each "direction" independently, ignoring flow control lines. There is one signal, which must somehow convey "data", but it must also be able to convey "no data". To convey "no data", we simply leave the signal high - logic 1. ...


8

If you need to do this programmatically reading the output from dmesg can be troublesome, instead the folder /dev/serial/by-id has sym links that are named after identifiable data of your device and point to the specific /dev/tty* they are connected to. I'm not sure if this is some special udev rule that is distribution specific, but it works well in Ubuntu,...


8

Little bash script: From sawdust's answer, there is my solution: for bauds in $( sed -r 's/^#define\s+B([1-9][0-9]+)\s+.*/\1/p;d' < \ /usr/include/asm-generic/termbits.h ) ;do echo $bauds stty -F /dev/ttyS0 $bauds && echo Ok. done 2>&1 | pr -at2 Will render on my host: 50 Ok. 75 ...


8

I ran into the exact same issue trying to connect to a serial device at 115200 baud. I am running RHEL V5. uname -a Gives: Linux localhost.localdomain 2.6.32-100.0.19.el5 #1 SMP Fri Sep 17 17:51:41 EDT 2010 x86_64 x86_64 x86_64 GNU/Linux After some digging I found this: sudo screen /dev/ttyS0 115200,cs8,-parenb,-cstopb,echo or this: sudo screen /...


8

I believe the picture shows a general RS-232 full-size DB25 COM port, and not a parallel port. Technically the stack-up should work with a special USB/PS/2 compatible mouse, which operates in LS USB mode (1.5Mbit/s). However, the picture shows a USB stick, which can operate only at FS rates (12Mbits/s) and above. This "setup" will not work because the setup ...


7

The connectors themself arn't actually specific to a protocol - It simply refers to the number of pins and that its sub miniature. You could in theory wire up any suitable connector to the right electrical connections and to use it. In most systems I've seen, serial ports had 9 pins (since they didn't implement the whole 25 pin standard). I could also have, ...


7

The PuTTY program is not built into Linux. What the other person meant is that most Linux systems come with commands that provide the same functionality as PuTTY: The SSH client is ssh. The Telnet client is telnet. The serial console clients are screen and minicom. To connect to the first serial port using screen, run: screen /dev/ttyS0 Press CtrlA ...


7

I think socat has the functionality you are looking for as well. $ socat TCP-LISTEN:4161,fork,reuseaddr FILE:/dev/ttyUSB0,b57600,raw


7

Try sudo screen /dev/ttyUSB2 115200,cs8,parenb,-parodd,-cstopb From the man page for stty: csN - set character size to N bits, N in [5..8] [-]parenb - generate parity bit in output and expect parity bit in input [-]parodd - set odd parity (even with '-') [-]cstopb - use two stop bits per character (one with '-')


6

You can check the device baud rate using the "stty" command on the console: $ stty < /dev/tty.. (where tty... is the device file you are listening) output: speed 9600 baud; line = 0; -brkint -imaxbel You can also change the baud rate with the following command: $ sudo stty -F /dev/tty... 9600 (or whatever baud ...


6

After thinking it through and finding a single post which was a little bit in the right direction I figured out it is the only remaining possibility to invert the signal and give it a try. Fortunately FT232RL has option flags in it's EEPROM (programmable with "MProg" by FTDI) to set this: After this, everything worked on every Baud rate. Don't ask me why, I ...


6

Well, really the answer here is because that's the specification, but that's a bit of an oversimplification obviously. Let's talk about RS232 ("serial"), and that answer is sort of broadly applicable in the sense of "the manner in which these things are generally designed (at least at their most complex)". In the case of RS232, you are correct - only two ...


Only top voted, non community-wiki answers of a minimum length are eligible