I have 2 computers running windows 7.
There are simply networked via LAN cable. One is Master and the other Slave. No Internet connection is available.
WHAT I NEED TO DO:
Each time both windows logged in and connected via LAN to each other, the Slave one sets its clock according to the Master's clock without third party user interference. How to implement this scenario?
Thanks in advance.
Having a LAN connection you can setup a synchronized clock among your machines using NTP. It is a protocol which works with great classifiers to keep count of the clock.
Here's a small client that might help you to keep up with the clocks of a few computers running windows, NetTime.
Related
I have a digital scale for trucks that is currently connected to a Windows XP computer that is unusable because of all the bloatware and viruses installed in it and the fact that the pc is 15 years old and it can't be formatted because the software and drivers for weighing the vehicles would be lost.
I'd like to develop a web application and configure a pc with Ubuntu Server running LAMP, and upgrade the whole thing so I can get rid of the old XP computer and work everything from a web browser.
I can connect and process the serial data using either NodeJs or Python, but I did that by connecting to the scale directly with my laptop.
What I need is to be able to connect to the serial port from another office where the PC with Ubuntu Server will be.
Is it possible to attach the digital scale to an ethernet adapter that doesn't require a host computer ???
My main problem is that I need the server to not be in the same room where the scale is and ethernet is my only option since there is an ethernet cable that runs undeground to where the scale is and is connected to a small switch which the people that weigh the trucks use.
I guess one option would be to use a Raspberry Pi maybe (since it's small enough) to connect the to the LAN and to the scale, and transmit the data whenever the server requests it, but I don't know if maybe just by using a converter only, the server could connect to the scale and get the data without the use of a host...
Any help would be greatly appreciated!
My work involves interacting with legacy hardware that uses serial ports. I often have to monitor more than one serial line, and for the purpose I have a couple of the common USB serial adaptors. When I connect both of them to the same (Windows 10) machine, irregularities show up. Both ports show up in device manager, but only the first one that I plug in to the USB connector works. The other one indicates port not open when I try to send data via RealTerm.
I have also seen the situation where when I plug the second adaptor in, its port comes up, but the one for the other adaptor disappears. Does anyone know a way that two devices can happily coexist on the one machine? Thanks in advance.
Just ion case this helps anyone in the future......
The problem seems to be caused by the fact that one of the adaptors was coming in via a (powered) USB hub. When I liberated another native port on the machine so I could host both serial adaptors directly, everything worked fine.
Not worth hunting the cause down, a solution is at hand.
I'm using my computer remotely and have an Arduino Every attached to a powered USB 3.0 hub. Anyway, the Arduino is part of a hardware tool that does some nice things for me. I communicate with it through the COM port.
The problem is that sometimes, after several days or even weeks, the Arduino's COM port just disappears. Is there some way to recover that COM port without physically unplugging it?
Sometimes restarting the computer works, but since the Arduino is plugged into a Powered USB Hub, it doesn't lose its power during a computer reset, so it doesn't reset itself and the COM port doesn't show up.
This used to happen frequently when I was using Arduino Nano knock-offs. I changed over to using Genuine Arduino Every devices and it hasn't been a problem for the last couple months. However, I'm now seeing it happen again.
Does anybody have a solution for this problem, or is this just something that happens from time to time with an Arduino when its connected for weeks/months at a time?
So, I replaced all usages of String with char[] and the problem still persisted.
I finally went online and purchased an internal PCI-E USB expansion card with 7 ports. I started using that 2 weeks ago and haven't seen the problem since. The other benefit to the internal card is that when I reboot the computer, the card reboots and forces a disconnect/reconnect of all COM ports.
I guess there was just something about having an external USB Hub that was causing the problems in the first place and the internal card was much more stable.
UPDATE - After week 3, I lost communication with a couple of my Nano Every devices. Unplugging and replugging them in fixes the problem, but I need them to NOT have that problem again. I guess the internal PCI-E Usb Hub didn't solve the problem. Maybe if I plug the Every's directly into the Computers standard USB ports that might help. I'll give that a try...
UPDATE 2 - I ended up purchasing a couple wifi wall plugs. Now, I can remotely unplug my computer and remotely unplug the USB Hub Power. I just 'Shut Down' my computer remotely and then remotely power it off for a few minutes and power off the USB hub for a few minutes. I then power up the computer (I have it's BIOS set to auto boot on power-cycle) and after it boots up, I power up the USB HUB and get all devices recognized again. Sometimes, I can just power-cycle the USB HUB to get the COM Ports visible again. It's a pain, but unless somebody comes up with a better idea, that's what I'm goin' with...
How to construct & send the magic packet for Wake on Wireless LAN?
The Wikipedia article on the subject only describes the standard Wake-on-LAN magic packet. However the same article describes that a supplementary standard would need to be used for waking up wireless hosts.
... If the computer being woken up is communicating via Wi-Fi, a supplementary standard called Wake on Wireless LAN (WoWLAN) must be employed....
Unfortunately I can't seem to find an authoritative source / method on how to implement Wake-on-LAN that for waking up nodes on WiFi.
The blog that wikipedia linked to say:
The simple fact is that there is not enough industry support for WoWLAN to make it feasible for most organizations.
From TCP/IP Illustrated volume 1:
using PSM (power save mode) can affect throughput performance significantly as idle periods are added between frame transmissions and time is spent switching modes
So I am not sure you really want this feature.
I am not sure if there is a RFC standard about WoWLAN, but there exists PSM in 802.11, which make station into a limited power state and can be woke up by AP. In order to wake the station that in PSM, you just need to send your data message to it, and AP will notify that station in next Beacon frame.
Update:
Some notice:
Only newer Macs support Wake-On-Lan over Wifi. If your Mac is a 2012 or older model, it probably does not support this feature.
You cannot wake from off or hibernate mode the way you can on a PC. You can only wake it from sleep mode. Also note that after a certain amount of time sleeping they will hibernate automatically. You can check this with the pmset -g command. I believe it's the StandbyDelay setting.
Some steps:
Configure your Mac to allow wake from Wi-Fi in the power adapter section of Energy Saver
Use Remote Desktop or an equivalent tool to send the Wake-on-lan (WOL) packet to your router that will then deliver it to your sleeping Mac.
Use some tools like wireshark to view the magic packet structure and protocol, then you can try it through WiFi.
Ref:
wake-on-lan-wol-over-wifi-not-working-on-mac
how-do-i-remotely-wake-my-mac-over-wi-fi
Apart from the above links pointed by Tony, I think the below link for WOL (wake on lan) works for Wake on Wifi as well. If you are not using iphone as a client to wake up as mentioned in the article, you can use any other WOL apps for your client machine:
http://osxdaily.com/2013/12/14/wake-on-lan-mac-iphone/
Hope it helps!
Is it possible to determine programmatically what jack on a network switch a computer is connected to?
It's either possible or not possible, depending on the switch.
If it's a managed switch, you could query its management interface to determine the MAC addresses behind each port. Then you could match that up with the hardware address on the computer you're interested in.
Some switches have discovery protocols (such as CDP or LLDP) which will broadcast the port's identity to whichever devices are attached. You could sniff the network for these packets to determine the port your computer is connected to.
You can try disonnecting them one by one and each time testing if the network connection goes down.
To identify switch port connected to your pc ; you need to manually access the switch and remove ur rj-45 cable so you can visualize any port having state of disconnection.. dm gui can be used if switch is managable
cdp and lldp wont work for pc as it doesnt support it