How Far Can I Run My Cable?

custom cable manufacturersBelieve 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.

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:

RS232 Cables V.35 Cables RS232 Extenders
RS232 Converters  RS485 Converters  Cards and PCMCIA Adapters
Serial Auto Switches


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

Standard or Generic Multiconductor
Part Number Cap. Per Foot Cond. Size
CAB004 33 pF 24 AWG (7×32)
CAB006 33 pF 24 AWG (7×32)
CAB009 33 pF 24 AWG (7×32)
CAB010 33 pF 24 AWG (7×32)
CAB012 33 pF 24 AWG (7×32)
CAB015 33 pF 24 AWG (7×32)
CAB020 33 pF 24 AWG (7×32)
CAB025 33 pF 24 AWG (7×32)
Low Capacitance Cable
CAB004-LC 15.5 pF 24 AWG (7×32)
CAB006-LC 15.5 pF 24 AWG (7×32)
CAB008-LC 15.5 pF 24 AWG (7×32)
CAB012-LC 15.5 pF 24 AWG (7×32)
CAB018-LC 15.5 pF 24 AWG (7×32)
CAB025-LC 15.5 pF 24 AWG (7×32)
UTP Solid Wire
Category 5 15 pF 24 AWG (solid)
Category 6 15 pF 24 AWG (solid)


Antenna cables: Specifically antennas for wireless networks, the length limit depends on the size of coax;

Coax Type Length Limit
RG174 (.11″ OD) 10 feet
RG58 (.21″ OD) 50 feet
LMR400 (.41″ OD) 100 feet
LMR600 (.60″ OD) *150 feet

*If the transmitter has a stronger signal, the length can go further on LMR600.