Believe it or not this is a pretty popular question. With all the different types of interfaces (Serial, Parallel, 10Base-T, 100Base-T, USB, IEEE-1394 FireWire, IEEE-1284 Parallel and Antenna for Wireless networks) it gets pretty crazy so lets see if we can make it a little easier on you.
| Serial: |
To determine the maximum length, some will say that the total capacitance cannot exceed 2500 pF. Every cable has a “capacitance per foot” rating (Scroll down to see the Cable Capacitance Guide that shows the capacitance per foot on our common wires). In order to determine the total capacitance, just take the capacitance per foot and multiply it by the length in feet. Or to determine the maximum length on a cable, take 2500 and divide it by the capacitance per foot. For example, if you have a wire that’s 15 pF/Ft, and made a 150 foot cable with it. The total capacitance is 15 pF/Ft times 150 feet or 2250 pF, still within the limit. On the other hand, you want to determine the maximum length of this 15 pF/Ft wire, take 2500 and divide it by 15 to get 167 feet as the maximum length.
| Examples |
| 15 pF/Ft x 150 feet = 2250 pF |
| 2500 pF (max.) ÷ 15 pF/Ft = 167 feet (max.) |
To see our list of serial products and custom cables click one of the following categories:
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| 10Base-T or 100Base-T: |
The total length of wire segments between a PC and a hub or between two PC’s cannot exceed 100 Meters (328 feet or about the length of a football field). To see a list of our networking products, click one of the following categories: 10Base-T and 100Base-T, NIC, Repeaters, Hubs, Switches, Print servers, Transceivers, or Converters. |
| IEEE-1284 Parallel: |
With the older style “Centronics” parallel, the length limit is typically 9 to 12 feet although some 30 foot connections have worked. The IEEE-1284 can go up to 50 feet in length. To see a list of our parallel products, click one of the following categories: Parallel, IEEE-1284, Converters, Extenders, IEEE-1284 Auto switch boxes, Parallel Auto switch boxes. |
| USB: |
In practice, the USB specification limits the length of a cable between full speed devices to 5 meters (a little under 16 feet 5 inches). For a low speed device the limit is 3 meters (9 feet 10 inches). most manufacturers do not recommend and will not support cables longer than 10 feet, although there are active extensions available that will allow longer runs ADP31802-xx, or extenders that will allow you to have a USB Run 150′ over Cat 5 cable, ADP3185. To see our manual switches for USB Click Here |
| IEEE-1394 FireWire: |
FireWire cables use 28 AWG wire and are limited to 4.5 meters maximum cable length. To see a list of our FireWire products, click one of the following categories: FireWire, PCMCIA card and Hubs |
Cable Capacitance Guide
| Antenna cables: |
Specifically antennas for wireless networks, the length limit depends on the size of coax;
*If the transmitter has a stronger signal, the length can go further on LMR600. |
