20 feet is the longest I know of
The longest Xbox 360 Ethernet cable you can use is typically 100 feet (30 meters). Using a cable longer than this can result in a loss of signal quality and slower connection speeds. It's best to keep the cable length as short as possible for optimal performance.
It depends on the length of th cable and the diameter of the copper cable used.
longest i have seen in a store was 100ft but if you need longer get a roll of Ethernet cable and 3 ends for it then make your own length of cable.
RS-232 standard is 50 feet.
About ten feet long
IEEE 1394b
The Cable Cat 6 is an Ethernet cable that supports fast Ethernet 10G BASE-T. This cable is available in a 20 meter length online from various retailers including cabling4less.
Scsi Cable (or more commonly know as the ribbon cable)
The weight of a cable can vary depending on its length, thickness, and material. On average, a standard HDMI cable can weigh around 0.2-0.5 pounds per foot.
Original answer:firewire IEEE 1394bImproved answer:IEEE 1394b
It looks like any other low voltage cable, such as a CAT-5 Internet cable. There are several variants to the RS-232 standard. The standard defines a 25 pin configuration for serial data communications. In many cases fewer conductors are used. Google RS-232 standard for definition of the connectors, cable length, restrictions, baud rates and voltage levels.