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Options for Adding Serial Ports The serial port is prevalent on PC's as well as scores of industrial, scientific and consumer devices, making it a convenient starting point for communications. Since RS-232 itself is only suited to short connections (50 ft. max.) many applications require that it be adapted to fit requirements. RS-422, typically used for extending RS-232 communications, provides full duplex communications between two devices. It can also provide one way communications from one master to several slaves. RS-485 communications standard allows cable lengths up to 4000 feet. It also provides very high noise immunity. Multidrop connections up to 32 different nodes can be made over a single twisted pair cable along with a signal ground connection. This article summarizes the choices a system designer has when adding a serial (RS-232, RS-422, or RS-485) communications device. There are many different ways to add additional serial ports to your Desktop PC, Palm, or Laptop PC. USB, PCMCIA, PCI and ISA are some of the methods that will be discussed. The Universal Serial Bus (USB) provides a high data rate and Hot Swap connection for PCs, providing an easy connection to a wide variety of multimedia and network USB devices. Generally considered to be for home or office use, USB is finding its way into Industrial applications. PCMCIA Serial Ports are yet another way to add serial ports to a PC that has PCMCIA Slots available. Most Laptops today offer only one (if any at all) DB9 type serial ports. A PCMCIA Serial Card is a good way to add a serial port (or ports) to any laptop that is low on available serial ports (RS-232, RS-422 or RS-485). PCI Cards are becoming more popular as a way to add serial ports to desktop PC's. PCI type slots are becoming the "norm" in standard PC's today, and PCI Serial Cards are an excellent way to add serial ports. The standard Desktop PC may only come with one serial port standard (if any serial ports at all). PCI Serial Cards use Software Drivers to address the ports to the PC. ISA Cards are yet another way to add serial ports to the older desktop PC's. ISA type slots are becoming scarce in standard PC's today, but are still an excellent way to add serial ports. The ISA Cards are typically addressed using dip switches and shunts or jumpers to set IRQ's for each port. No Software Drivers are required with ISA style serial cards. Palm OS PDA's may be connected to RS-422 or RS-485 data circuits using Palm adapters. These adapters offer total portability for collecting data and field service chores. The Palm device and the adapter will usually slip into a shirt pocket. Some models use the PDA's connecting cable, some include a cable and some are cradles that allow the PDA to nest in place and connect directly to the Palm base socket. PalmTerm Freeware allows you to transmit and receive data from the Palm serial port.

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How do I connect a 180e serial cable to my usb computer when Artlink and CPS software specify serial port?


I've not successfully managed this ... trouble-is that although you can get USB-to-serial converters, most computers that only have USB ports do not properly 'recognise' COM ports, which is what your Artlink software expects to talk to. I still use an old PC with a 'proper' 9-pin serial port on the back in order to talk to the old Artista range of machines. One of the drawbacks of a 'throwaway' PC industry that expects the rest of the world to continually update everything in response to new interface standards!

Oct 08, 2011 | Bernina Artista 180

1 Answer

Both printer and 9 pin serial ports not working


What has changed? One solution is to go into BIOS when you first turn on your PC hit <del> key. Make sure the ports are enabled. The second solution is to make sure you didn't add a device with serial ports or something which is sharing the same IRQs, which is 3 4 and 7 traditionally (for COM1/2 and parallel port).

If you tried all this and it doesnt work, then somehow the chip on the motherboard which handles these (the UART chip) has broke, you need to replace the motherboard or buy a card with serial and parallel ports on it (this should be quite cheap, ie 10-20 dollars).


Nov 07, 2009 | Intel Computers & Internet

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what do "ports" mean when adding printer?


An interface on a computer to which you can connect a device. Personal computers have various types of ports. Internally, there are several ports for connecting disk drives, display screens, and keyboards. Externally, personal computers have ports for connecting modems, printers, mice, and other peripheral devices.

Almost all personal computers come with a serial RS-232C port or RS-422 port for connecting a modem or mouse and a parallel port for connecting a printer.
On PCs, the parallel port is a Centronics interface that uses a 25-pin connector. SCSI (Small Computer System Interface) ports support higher transmission speeds than do conventional ports and enable you to attach up to seven devices to the same port.

In TCP/IP and UDP networks, an endpoint to a logical connection. The port number identifies what type of port it is. For example, port 80 is used for HTTP traffic.

Also see Well-Known TCP Port Numbers in the Quick Reference section of Webopedia.

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Mar 16, 2009 | Panasonic Toughbook CF-51 Notebook

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Gps


Hi fire1961,

Downloading data from my FURUNO GP-30 gave me no problems. But it took me long time to figure out why I coudn't upload waypoints and routes to the GP-30 via the serial port in my ThinkPad T30.

I tried nearly everything tested the cable, tested a lot of different software and even wrote a little c-program to communicate with the serial port. I also tried a serial-to-usb converter with no results. Then I stumbled over this RS232 Tutorial. According to this - serial ports are not just serial port but can be divided into three general categories:

The types of driver ICs used in serial ports can be divided into three general categories:

* Drivers which require plus (+) and minus (-) voltage power supplies such as the 1488 series of interface integrated circuits. (Most desktop and tower PCs use this type of driver.)
* Low power drivers which require one +5 volt power supply. This type of driver has an internal charge pump for voltage conversion. (Many industrial microprocessor controls use this type of driver.)
* Low voltage (3.3 v) and low power drivers which meet the EIA-562 Standard. (Used on notebooks and laptops.)

Then I installed the waypoint upload software to my ten years old Compaq Presario and suddenly I could upload routes and waypoints but only via the on board serial port. The serial-to-usb converter didn't still work.

So if people experience no result trying to upload data to these old GP-30's from their notebooks and laptops. Then I think it could be a matter of these Low voltage ports not are able to provide the FURUNO device with enough voltage. See the above RS232 Tutorial.

Best Regards

Lars Erting

Aug 03, 2008 | Furuno GP31 GPS Receiver

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