I want to know how can i use 2 GSM Modems in one computer (using Windows) ?
Those modem have a usb connector but the system plug them as Mobile Modem in COM Port.
The probleme is how to use 2 Modems togeteher in different ports.
The modem reference is ls100 and it made by Lonsai i connected 2 modems in my computuer but in devices manager i found the COM Port of the first one that i put. did some one have an idea how to detect 2 COM Ports ?
Thank you.
If you are using serial port then that is not possible ofcourse. However, if you are using USB to connect the modem, you can use different COM ports. Here are some steps you can try and debug the issue:
Please refresh your device manager settings and see if you can find another COM port.
Plug in the modems one by one to see if the COM Port appears for both. Note what number has been assigned to each modem.
Try using different USB ports on your PC.
Try using a different terminal to see the COM Ports or multiple terminals for each modem
Related
Currently I have a server, that communicates with a projector through a RS232. The server opens a com port when the projector is connected. The same happens to any PC when a certain type of device is connected through the USB (lets say an Arduino for example). What I want to do it basically replace the projector with a PC/Arduino/Raspberry without the server noticing anything. That would mean the server will recognise the connected PC and open a COM port for it. What do I need to do on the PC so that it automatically opens a com port on the server? I guess there is something very basic that any printer, Arduino, projector etc does, that computers recognise it as a "com port device".
P.S. Doesn't matter the OS on the PC, I just need to make it work and then implement w/e I need to do with the established communication over the port.
P.S.2 I've searched a lot about it, but probabl I am doing it wrong, because I didn't find my type of question anywhere.
COM ports are basically hardware that is detected by the system. Let's say, if an Arduino is connected to a PC, it has its onboard USB to TTL converter which can be found in the device manager(if using windows). Similar USB to TTL converters are there in the market like CP2102, PL2303 which acts like a COM port even if no device is connected further to it. it may be possible that the program you are using(as you referred server) may be sending some data over the serial port and verifying the hardware.
What you need to do to replace it is, first of all, find the baud rate at which the communication is going on, then, listen over the serial lines which machine is sending which message in the sequence(there must be a handshake as I mentioned earlier), if a complicated algorithm is not used by the device, you can simply mimic the device by sending same messages over serial.
I would like to develop my own modem for a custom communication network that will be detectable on the serial port by PC automatically. What I'm uncertain about is the protocol part of the AT commands and how to make it work seamlessly so that computer will detect the modem automatically.
I plan to use ftdi UART to USB converter to interface my microcontroller with the PC using standard serial interface. The PC will then use AT commands to communicate with the microcontroller that will in turn connect to another microcontroller over radio tranceiver and establish a two way serial connection over radio. The idea is that the PC on the other end will run PPPD and listen on it's own modem connection for incoming call and then bridge the connection with it's other internet interface that is connected to internet. The first computer will get it's own IP address using PPPD and will be connected to internet over this custom microcontroller based modem.
But how do I implement the communication protocol between my controller and PC? What commands do I absolutely need to implement? How do I make sure that the computer recognises my controller which is connected over ftdi usb to serial adapter as a functional modem?
Where can I find a speciffication of the minimum command set that is required of a modem?
In practice linux usually discovers a 3G modem automatically for example. Does that have to do with the actual USB identifier of the modem? Is it possible to have linux automatically discover an ordinary serial port modem? I'm thinking that the modem will be sending an AT idle ping repeatedly when it's plugged in so that linux should be able to detect it.
I have 2 linux computers. For security, I want to setup a link between them, then program a library for sending/receiving data over this connection. I know that we can use USB networking cable for connection. But I am not sure is it possible to send and receive data on this link, does it depend on cable manufacturer? And Can I program library without using cable driver?
You can't use a USB cable to connect two computers with standard USB interfaces. Standard USB interfaces on computers are host interfaces and you can only connect a host to a device, not another host.
The "cable" described in the article it's not just a cable, the correct name would be USB host-host bridge controller and it powered by a chip designed and manufactured by Prolific - PL 2501. It's described also in the article.
As David Schwarz said with dumb cable (only the wires) you cannot setup a link between two PCs, because USB it's master/slave bus, where a device it's the slave and other the host. The PC it's designed to always be the host (the master).
The response it is that you cannot setup a link or do networking between two PCs using a dumb USB cable. You can do this only using a bridge like the one described in the article.
I am using RXTX with Java to connect to serial port. But now i have to test whether the communication is working properly or not? How to do this. Do i need modem or can we test any way in my local with out modem.
this is the program i want to test http://rxtx.qbang.org/wiki/index.php/Two_way_communcation_with_the_serial_port
On Windows you can use a 'null modem emulator' called com0com. This registers 2 dummy com ports onto the OS, which will communicate between each other.
So, you'd need to connect to it 'twice', one for each end of the serial connection.
com0com also has variants called com2tcp & hub4com, if that's more appropriate for you.
HTH
Uh, no you don't need a modem(?). You can use a null modem serial cable to do loopback testing from one COM port to another. You can do this on a single PC or two different computers. If you don't have enough COM ports, use a USB to serial converter.
So, this topic is very similar to this Cisco Switch/Router programming using Arduino?.
I have an Arduino ATmega2560 and Ethernet Shield plus a Cisco 1751 router. I want to configure the router via the console or AUX port using Arduino.
Fast search gave the following results: you could connect to the router using RJ45 to Serial or RJ45 to RJ45 connectors; the protocol is very similar to Telnet (actually works like serial port with text-based commands).
So the main question is - am I able to control the router via a console or AUX port using Ethernet Shield (and an Ethernet library) or do I have to use a serial port connection using something like RS-232?
Update: I've noticed one thing - the DB9 port is just an option for easy communicating with a PC so it seems that my idea is not so bad:) See Cabling and Adapter Setups that Work.
As you have pointed out the console and aux ports on Cisco devices are serial ports not network ports so you need to connect to them using RS232, this is an entirely different type of interface from Ethernet.