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Questions tagged [serial]

The general purpose communication interface and related protocols. Specifically, a serial interface transfers one bit at a time ("in serial"), and complies with the RS-232 standard.

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Dedicated connections/text outputs for communicating with serial devices [migrated]

I am a software developer currently entering the world of programming for physical devices through a serial interface and some aspects are foreign or unknown to me. One such aspect is figuring out ...
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Serial WAN link failure

I am trying to connect two Cisco 3945 ISR’s with HWIC-4Ts via a RS-232 (DB-25) Null Modem cable. When I connect the routers they refuse to show any line or protocol connectivity. The cables are known ...
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How to troubleshoot emulated RS232 communication to Verifone MX915

We have many Verifone MX915 devices in our production retail environment. Since implementation, the MX915 devices have had UI lockup problems. Through a lot of trial and error, we determined that ...
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2answers
225 views

Can't get grub2 boot menu via COM2 port

I want to connect my "CentOS Linux release 7.6.1810 (Core)" device via COM2 port,then I modify '/etc/default/grub': GRUB_TIMEOUT=5 GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)" ...
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24 views

The simplest test for a dumb terminal (VT525)

Having read a lot of answers here and on the raspberry pi SE site I can find nothing wrong with my configuration or my cable. The final conclusion is that I have a bad terminal. Is the quickest test ...
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1answer
23 views

T0 vs S0 in inittab for serial ttyS0 access

I can't find any documentation on what the difference between "S0" and "T0" in the inittab file for granting serial access to console is. People seem to use it interchangeably: T0:12345:respawn:/sbin/...
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31 views

Cisco Serial Connection issue

So I have been trying to get into my Cisco switch without the password, which involved power cycling the switch and pressing the mode button, prior to doing this I was able to type in Putty console ...
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1answer
25 views

Serial over USB during boot

I am currently trying to debug the boot sequence of Xen, and past a certain point, the only way to do it is over a serial connection. Now, on the laptop I'm using there exists no serial port nor an ...
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175 views

Serial terminal servers that work with “serial-over-USB”

I've used serial terminal servers for a long time. Basically, these are devices that allow you to communicate with a serial (eg RS232/RS485/RS422) device over ethernet in various ways. Folks in this ...
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1answer
939 views

PPP / 3G modem not getting an IP: No network protocols running

Modem in use: SIM5310 connected to an ARM based board. root@cm-debian:~# uname -a Linux cm-debian 4.4.0-cm-t335-5.1-00030-gd350d89-dirty #29 SMP Sat Nov 4 19:18:48 PDT 2017 armv7l GNU/Linux I am ...
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1answer
344 views

Telnet through a serial terminal server

I have a Perle IOLAN device like this, and one configuration option is for a serial terminal. The corresponding configuration screen. As you can see, one option is to configure the terminal to ...
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2answers
1k views

how to use ssh over serial without using pppd? ( Or how to transfer TCP over serial without using pppd)

There are many virtual machine based on QEMU in my server. Some of them are forbbiden to use networking, and only way to attach them is via virtual serial port. Due to serial console's bad features (...
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2answers
724 views

HP Procurve 2650 has password set after factory reset

I have a problem with HP ProCurve 2650 switch. I don't have a password to it so I did a factory reset (pressing reset and clear buttons for 10 seconds). The problem is it still asks for the password. ...
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2answers
94 views

Connect Raspberry Pi to Windows Server (HP DL380) over serial connection

I have tried searching the internet for many hours on this issue and I haven't found anything that would fit my needs. Here is the problem: We have some HP DL380 servers in a network that is closed ...
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1answer
80 views

Linux: logoff the user after its serial console terminated

I connected to Linux (in the case here, I used Ubuntu 1604) by serial console. Now, the serial console is closed (terminated), but, when I connect back to the serial port again I saw all the sessions ...
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1k views

Serial port console connection to Network Switch

I have a network switch (an HP Procurve) that provides a command line interface that can be accessed via a direct serial port connection. The direct connection is done using an RJ45 connector on the ...
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2answers
58 views

RS232 to USB extension cable to network configuration

I'm not sure this is the correct place for this question. I have a console cable to configure network devices like switches (https://images-na.ssl-images-amazon.com/images/I/41LDstMTA5L.jpg) So, I ...
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182 views

Avocent Cyclades Serial Switch Disable Telnet Login message

Whenever I open a telnet connection via PuTTy to a serial port on my Avocent switch, it will print something like the following message: Sharing connection with other user(s): 'NONE@525', 'NONE@546'...
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1answer
6k views

QEMU and serial ports on the guest OS

Has anyone successfully managed to run a Guest OS in QEMU/KVM where the guest has full access to the Hosts serial port(s), be it /dev/ttyS0, COM1, or a virtual serial port provided by the Host. It ...
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699 views

Can't send commands to server via Serial connection in putty/termite

I acquired a Sunfire v215 server from work (they were recycling it) to fiddle around with in my spare time. I'm trying to start it up - the installation guide says you need to use a serial terminal or ...
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1answer
76 views

Setting up a three way serial port from a single existing port

I currently have a device that has a serial port, and on boot this serial port is bound to ttyS1. There is a process on the device (that I have little control over) that takes control of this port so ...
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1answer
676 views

Serial Port in KVM Virtual Machine

trying to configure a KVM Virtual Machine with a Serial Port mapped from the host, something like : <serial type="dev"> <source path='/dev/ttyACM4'/> <target type="isa-...
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1answer
72 views

Unable to attach additional serial ports to a RHEL6 server with 8 serial ports

I have a RHEL6.9 server with 8 serial ports attached. RHEL has configured 4 of them /dev/ttyS0-3, they have addresses and IRQ's. I've been using the mknod command to create the devices /dev/ttyS[0-3]....
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2answers
1k views

How to tunnel the serial port from a remote machine?

I'm trying to access a remote serial console (a tty port on a remote machine) as if it's on a local machine. This is necessary for a serial-port only application to work on my machine. The remote tty ...
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3answers
13k views

How to enable and use the serial terminal of a HP Microserver Gen9?

I have a HP ProLiant Microserver Gen9. It has HP ILO version 4, but the Java based Remote Console doesn't work reliably and I can't use it after the POST screen in the free version of ILO (asks me to ...
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1answer
87 views

Remotely connect to Hyper-V guest before OS boot?

I have several guest VMs that use Truecrypt full disk encryption running on a Hyper-V host. What are my options to allow VM owners to enter their own password to boot the machine?
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2answers
2k views

Connect to switch's console port through etnernet patch panel

In our office building, we have a Cisco SRW2048 switch. On the back, it has a serial port for console connections. I would like to connect this console port to my computer in my room. The switch is ...
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1answer
477 views

Cut Off My Own Google Cloud Engine SSH Nose

A bit of stupidity. On my Google Compute Engine (GCE) instance, I went in and changed the sshd_config to listen another port (something I do routinely)...but I didn't test before logging off. And ...
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1answer
28 views

Are the tty parameters stored somewhere when using screen?

Here is the story: From a fresh install of ubuntu I use a serial to usb device. screen /dev/ttyUSB0 everything goes fine and I can interact with the device perfectly. Then I unplug this device, plug ...
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1answer
1k views

How can I connect to a cisco switch via serial console cable from powershell?

I don't actually need to perform any operations on the switch. I just need to verify it's there. I have some remote servers that I need to verify have the blue serial console cable hooked up ...
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2answers
7k views

APC Smart UPS serial connection on Windows Server 2012 R2

I have an APC UPS 620 and a Windows Server 2012 R2 (non virtual) server. The server and the UPS are connected with genuine APC serial signaling cable. Without installing any software the APC is not ...
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1answer
3k views

How to connect a switch and a router to laptop via putty

I am new to configure a switch 2950 and a router 2651 to laptop using putty on my home lab. My problem is that after I connected my router through console cable to laptop I and decided to add a switch ...
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1answer
669 views

Minicom Serial Port Connection Output

I have recently purchased a Cisco PIX 501 firewall and I have connected to the console port with a serial port USB adapter. After doing this I open up my terminal and start minicom. Here are my ...
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1answer
2k views

Serial communication between QEMU host and guest

I'm trying to set up a pair of serial ports between my QEMU host (Debian Jessie x86_64) and guest (also Debian Jessie, but on ARM). Everything except the serial port part works. I'm really new to ...
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2answers
104 views

How to tell whether a serial connection is “established”?

We have a Debian-based embedded device. It runs an application that communicates with other embedded equipment via serial (RS-232, /dev/ttyS*). Usually, this works just fine. But of course, sometimes ...
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How to add a serial port to a Windows 7 guest VM using Xen server 6.5?

We wonder how to add a SERIAL PORT (COM2) into a guest HPVM Windows 7 64 bits in a xen server 6.5 bare metal hypervisor. We have some clients connecting through RDP v8.1 (from Win7-64 to Win7-64) ...
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1answer
435 views

VMware remote virtual serial port concentrator

I'm setting up a Cisco virtual wireless controller using the guide provided here: http://www.labminutes.com/wlc0001_vwlc_7_3_vmware_installation The narrator talks about making sure your VMware is ...
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1answer
151 views

Serialization with Ansible with a jumpbox/build-server

We are using a build-server that is delegating_to and deploying the build to the application servers. I am not sure how we are going to "serialize" since everything is being done on the build-server ( ...
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1answer
578 views

Why can't I connect to this switch ther the comm port?

I have an enterasys C2G124-48 switch that I need to set up some port mirroring on to troubleshoot some Voip issues. However I am having issues connecting to the switch through putty. I am following ...
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1answer
492 views

How can I get split one serial connection into two

I need to get an application and a monitor to read from the same serial port, the application will be the only program that will be able to read/write to the serial port and the monitor will only be ...
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0answers
77 views

Is there a way to use a server serial (com) port as a client to connect to a switch console?

I'm trying to connect an IBM idataplex 360 M4 node via it's front rs232 port to the console port of a switch with the switch's supplied cable, but I'm having no luck. The server is running RHEL 6.5 ...
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1answer
6k views

resetting Cyberoam cr 15i UTM console Password

i forget my cyberoam cr 15i firewall password and i reset the system. but now i cant login through console also. default password 'admin' is not accepting there. when iam connecting to console ...
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2answers
504 views

Cisco console, is possible to have DB9 split out to multiple RJ45's?

Cisco Serial Console cables are simply DB9 to RJ45. Of course many people have now come to use a variety of DB9 to USB adapters to get around many machines not having serial ports. But I'm more ...
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1answer
1k views

expect script running screen stops working when run by cron

I hope this question is OK for this forum. I have a device, a modem. I talk to this modem with the linux program "screen" as a terminal program. I invoke it like this "/usr/bin/screen /dev/tty6". I ...
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1answer
1k views

Palo Alto PA-4020 cannot connect to terminal through Serial to USB

I have a PA-4020 that I messed up the configuration on, and I am trying to do a factory reset. I went ahead and ordered a few different serial to USB cables, and cannot connect through a Mac App ...
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1answer
165 views

Tcp connection breaking, too fast for serial?

I've been having real difficulties getting a tcp connection to work with my web server. I think the issue might have something to do with the speed or ordering of the packets as the connection seems ...
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1answer
128 views

Raritan serial consoles (DSX) totally unreliable

We have some serial consoles by manufacturer Raritan. More specifically, 8-port and 16-port DSX-8 and DSX-16s. Currently, I seriously doubt their stability. What happens most of the time: Usually, ...
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2answers
2k views

How to replace a hardware modem by virtual modem

I have an embedded device that is connected by an old dial-up modem to the Internet. I cannot change the embedded device but would like to connect the embedded device to a Linux machine that has an ...
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1answer
1k views

hdparm serial number is garbage

I'm trying to read the model and serial number from a drive using "hdparm -I /dev/sda" and I find on some systems (eg: VMware virtual machines) the serial number and model often return garbage (see ...
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1answer
62 views

Telnet, Startech, and a Transmitter

I'm at a bit of a loss and will also preface by saying that I have very little experience working with Telnet. I have Startech Serial over IP 'webserver' setup, everything seems fine on this end. Next ...