DoIT Showroom Buyer's Guide

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Ethernet Splitters, Crossover Cables, and Jack Converters

Phone Splitters & Couplers
Splitter Type:	4 pair "Y" Ethernet Splitter USOC	Telephone cable Coupler	2 pair "T"
Connection Type:	RJ-45	RJ-11	RJ-11
Proper Usage:	This device splits a four-line (8-wire) RJ-45 USOC jack into two, two-line (4-wire) RJ-45 phone lines. Each of the resulting jacks will have two of the original four lines.	Joins two phone cables, making one continuous cable of longer length.	This splitter takes a two-line RJ-11 phone jack, and shares both lines with two jacks, allowing you to use the same two lines with more than one phone.
Usage Diagram:
Further Information:	Wiring Diagram Wiring Standards Info	N/A	N/A
Part Number:	C39111	C39106	C13589
Price:	$11.29	$3.49	$3.06

Network Splitters & Couplers
Splitter Type:	4 pair "Y" Ethernet Splitter USOC	4 pair "Y" Ethernet Splitter 568B Vertical Profile	BNC to BNC Thin Wire T-Adapter Ethernet Adapter	Ethernet Straight-Thru Coupler
Connection Type:	RJ-45	RJ-45	BNC (Coaxial)	RJ-45
Proper Usage:	This splitter is used to connect two computers to one USOC data jack that is wired for two ports. The jack must be wired for two ports, and the connector on your cable must be either RJ-11 ethernet (looks identical to a normal phone cord), or USOC-wired RJ-45 ethernet (looks like a wide-phone cord).	This splitter is used to split a 568B jack that is wired for two ports into two 568B jacks. The jack must be wired for two ports for this splitter to work, and your connectors must be standard RJ-45 ethernet.	This splitter (2) takes data from the network (1) and splits it to one computer. This line must eventually be terminated with a terminator or like-device at (3).	This coupler joins two Ethernet cables, making one continuous cable of longer length to connect any two network devices.
Usage Diagram :
Further Information:	Wiring Diagram Wiring Standards Info	Wiring Diagram Wiring Standards Info	N/A	N/A
Part Number:	C39111	C17031	C13581	C39279
Price:	$11.29	$14.95	$7.67	$4.99

Crossover Connectors
Splitter Type:	Crossover adapter 568B to 568A	RJ-45 to RJ-45 crossover cable
Connection Type:	RJ-45 male to RJ-45 female	RJ-45
Proper Usage:	This adapter (1) changes a normal RJ-45 - RJ-45 ethernet cable (2) into a RJ-45 - RJ-45 crossover cable (568B to 568A). This allows direct networking between computers without need of a hub or switch.	This crossover cable (1) allows direct networking between computers without need of a hub or switch.
Usage Diagram :
Further Information:	Wiring Diagram Wiring Standards Info Crossover Info	Length: 7 ft. Wiring Diagram Crossover Info
Part Number:	C22907	C26584
Price:	$11.93	$4.99

DoIT recommends that you talk to your network administrator before buying splitters

Wiring standards -- 258A, 568B, and USOC are wiring standards that networks use, 258A and 568B are synonymous with one another (the name 568B is more widely used). The different names denote alternate ways to configure the eight different pins on an RJ-45 jack or the six different pins on an RJ-11 jack. Of the six or eight wires that a jack uses to connect computers to a network, two wires are used together to send data and two wires are used to receive data*, thus the term "pairs" is is used. Because of this an RJ-45 jack (8 "pins" or wires) can have two ports if it is wired appropriately**.

Crossover cables -- 568A (or 258B) is a wiring configuration that is the exact opposite of the standard 568B (258A), which is why it is called a crossover cable. Put another way, the wires that are designated for transmitting and receiving are crossed over. One example of when you would want to use a crossover cable is when you want two computers to talk to each other without the use of a hardwired network. The crossover adapter will allow for two computers to communicate by crossing a signal sent from pin 2 (designated for sending) over to pin 6 (designated for receiving) on the opposite end of the cable which is connected to the second computer.

Connector size -- RJ-45 and RJ-11 describe sizes for jacks and cable connectors. The RJ-11 jacks are the same size as a standard phone jack and the RJ-45 jacks are about 50% larger. It is possible for RJ-11 connectors to fit into RJ-45 data jacks, which is the case for any of the USOC data jacks that were wired in the 1989 AT&T campus rewire.


**Most RJ-45 jacks are not wired for two ports. This sort of wiring will only be found in older campus buildings. If a data jack is not wired to support two ports then you can only
connect one computer to that jack. To allow network access to more than one computer through one jack in any of the building wired in the current way, a switch would be necessary.