Question 1

Why this so much while a switch with port mirroring (e.g. tl-sg105e, if only utilizing 3 ports) only cost $20? with due repect to the manufacturer.

Accepted Answer

A switch with port mirroring isn't a tap. The manufacturer of this tap did the work to design and implement a device which would NOT change the characteristics or timing of the A/B traffic flow. The design is not a  "standard cookie-cutter" implementation of a switch-chip's reference design. On the other hand, 5-port switches are as they say "a dime a dozen" and port mirroring and simple management protocols are now built into the silicon as standard features. 
Another reason for the price difference is the application. A tap is used in specialized circumstances, such as diagnostics or forensics, and that perhaps allows a higher price to be demanded, much like selling rope in a yachting goods store. The buying audience can bear a higher price.
My explanation is just a conjecture. You have to decide if the special tap features are worth the money.

Question 2

Will it work with a cable modem?

Accepted Answer

It will work with any Ethernet cable. Standard stuff. I recommend CAT6 or better. It will not work with a coax cable like RG6. It is not managed and provides no services like DHCP. It is a simple layer 2 switch with a hardware mirrored port (1 -> 5). It is permanently configured this way. If you want to capture packets on the wire going traversing a gateway, then this is great for that. Otherwise, it will act just like a regular un-managed switch.

Question 3

If this device fails will it fail open or block all traffic?

Accepted Answer

With no power, it will not pass traffic.

Question 4

Thinking about by. Anyone who purchased notices any network degradation in their environment where they have implemented their Tap?

Accepted Answer

We have not had any noticeable network degradation. We positioned out tap on our outgoing broadband connection (70/40 Mbps down/up) and have not had any deleterious effects.

ASIN	B004EWVFAY
Best Sellers Rank	50,619 in Computers & Accessories ( See Top 100 in Computers & Accessories ) 324 in Network Switches
Box Contents	ETAP-2003/ETAP-2003R unit and USB power cable
Brand Name	Dualcomm
Color	Blue
Compatible Devices	[Any device that supports a 10/100/1000Base-T Ethernet link]
Compatible Operating System Family	Linux, Windows
Customer Reviews	4.5 4.5 out of 5 stars (117)
Data Link Protocol	USB
Data Transfer Rate	1 Gigabits Per Second
Hardware Interface	Ethernet
Item Dimensions L x W x H	9.5L x 7W x 2.5H centimetres
Item Weight	12 Ounces
Manufacturer	Dualcomm
Manufacturer Part Number	ETAP-2003_SML
Model Number	ETAP-2003_SML
Number of Items	1
UPC	804879244066
Unit Count	1.0 count

ETAP-2003 10/100/1000Base-T Gigabit Network TAP

Details

Details

Description

Specifications

Common Questions