What is ripcord in unshielded twisted pair cable?

Typically a nylon cord within the sheath of the cable. It is designed to make it easier to remove the outer sheath by tearing through it.

Inside some UTP cable jackets is a polyester or nylon string called the rip cord, also known as the slitting cordor slitting string. The purpose of this cord is to assist with slicing the jacket open when more than an inch of two of jacket needs to be removed. Some cable installers love them; many find them a nuisance, as they get in the way during termination.

Reference: Oliviero, A., & Woodward, B. (2010). Cabling: The complete guide to copper and fiber-optic networking. (4 ed.). Sybex. Retrieved from Amazon.com/Cabling-Complete-Copper-Fiber-Optic-Networking/dp/0470477075/ref=sr_1_1?s=books">http://www.Amazon.com/Cabling-Complete-Copper-Fiber-Optic-Networking/dp/0470477075/ref=sr_1_1?s=books