Author: Kurt Weiske

EIA-TIA Cabling Specifications

Posted on by Kurt Weiske

rj45

Crossover Cable
RJ-45 PIN RJ-45 PIN
1 Rx+ 3 Tx+
2 Rc- 6 Tx-
3 Tx+ 1 Rc+
6 Tx- 2 Rc-
wirea
wire
Straight Through Cable
RJ-45 PIN RJ-45 PIN
1 Tx+ 1 Rc+
2 Tx- 2 Rc-
3 Rc+ 3 Tx+
6 Rc- 6 Tx-

Use a straight thru cable assembly,568B on both ends when connecting Hub to Xcvr or NIC Card. When connecting hub to hub, Xcvr to Xcvr, or NIC to NIC, the wires must crossover at the opposite end of the cable assembly,use the 568B on one end, 568A on the other end.

Interconnecting Your Hubs, Transceivers, and NIC Cards

A crossover cable is required when connecting a Hub to a Hub, or a Transceiver to Transceiver, or NIC to NIC card, or Transceiver to NIC card. When connecting a Hub to a transceiver or NIC card, a straight through cable is always used. Please Note: Some products are equipped with internal switches that can internally cross the twisted pairs.

 

10BASE-T Crossover Wiring

When connecting two twisted-pair MAUs together over a segment, the transmit data pins of one eight-pin connector must be wired to the receive data pins of the other, and vice versa. The crossover wiring may be accomplished in two ways: with a special cable or inside the hub.

For a single segment connecting only two computers you can provide the signal crossover by building a crossover cable, with the transmit pins on the eight-pin plug at one end of the cable wired to the receive data pins on the eight-pin plug at the other end of the crossover cable and vice versa.
crossover

FIGURE 5.2 10BASE-T crossover cable

However, when you are wiring multiple segments in a building it’s much easier to wire the cable connectors “straight through,” and not worry about whether the wires in the jumper cables or other twisted-pair cables in your building have been correctly crossed over. The way to accomplish this is to do all the crossover wiring at one point in the system: inside the multiport hub.

The standard recommends that the signal crossover be done internally in each hub port. If the crossover function is done inside a hub port, then the standard notes that the port should be marked with an “X.”

Photojojo’s Ultimate Hipstamatic Guide

Posted on by Kurt Weiske

Have you downloaded Hipstamatic from the iTunes store yet? It turns your iPhone into a retro camera with a number of effects. There are lens effects, film effects and flash effects that can be layered on top of each other.

A HUGE number of effects. Effects with bewildering names, like Kaimal, Helga (we can figure THAT one out), Dreampop, Kodot, Roboto, and my favorite, Jimmy.

Thankfully, the folks at Photojojo have come out with PhotoJojo’s Ultimate Hipstamatic Guide, showing examples of all 336 possible layered effects.

[via photojojo ]

Ciao, digital. Hello, unpredictable art.

Posted on by Kurt Weiske

From SFGate.com comes this article about the 2010 International Juried Plastic Camera Show at Rayko Photo in Francisco.

"Old Oak," a black-and-white photo by Robert Holmgren of Menlo Park, won the 2010 International Juried Plastic Camera Show's Best of Show award.

Plastic cameras are cheap, prone to light leaks and unpredictable. Which is why a lot of photographers are drawn to them in the digital age of pixel counts, precision focus and Photoshop.

“You don’t know how the image is going to turn out when you shoot with a plastic camera. The unpredictability is a big part of the draw,” says San Francisco photographer Carlos Arietta, one of the many artists whose work is on view in the RayKo Photo Center’s 2010 International Juried Plastic Camera Show.

Continue reading “Ciao, digital. Hello, unpredictable art.”

Cheap Coffee of the Week — MR. COFFEE DARK ROAST

Posted on by Kurt Weiske

I didn’t know Mr. Coffee sold coffee! This was on closeout at Walgreens, and brewed be a surprisingly nice cuppa. Medium to dark body, not overly bitter, and a nice punch to it – I made one cup to get me awake at oh-dark-hundred and made another cup in my travel mug for the road.

If you hurry, Walgreens still might have some left.

What: Mr. Coffee Dark Roast
Where: Walgreens
$$$: $3.99/10 oz.
Rating: 2 cans.