Frequently Asked Media and Rate Converter Product Questions

Questions:

1. What are the swap/Cross-Over UTP Cable pin-outs?
2. What are the maximum cable distances attainable on the Fiber to UTP converters?
3. I want to connect an older system with thin-net into my UTP network, what should I use?
4. I want to connect a Sun workstation with a UTP connection into my existing ethernet (thin-net) network? What should I use?
5. What is the difference between a repeater and a converter?

Answers:

What are the swap/cross-over UTP cable pin-outs?

• When connecting a workstation or server via a MAU (Media Access Unit) into a hub, you use a straight through cable. If you wish to connect two hub ports or two workstations together, you must use a swap cable, since both machines will try to transmit on the same pair, and receive on the same pair. A swap cable will route the transmit pair of one into the receive pair of the other. All 10BASE-T ports on MiLAN's physical layer products except our hubs, are wired like a MAU transceiver ports that you will find on a convertor. The pin-outs for a swap/cross-over cable are:

  1 -> 3

  2 -> 6

  3 -> 1

  4 -> 4

  5 -> 5

  6 -> 2

  7 -> 7

  8 -> 8

• The MIL-140/150 (Multi mode fiber) can connect at distances up to two kilometers. The MIL-160 (Half duplex single mode fiber) can connect at distances up to two kilometers as well. The MIL-170 (Full duplex single mode fiber) can connect at distances up to ten kilometers on Full Duplex mode and two kilometers on Half-Duplex mode. The 100Mbit converters have limits under 400 meters in half-duplex operation with minimum distances of (100TX) like 1 meter, but at full- duplex the 180T/180C multi mode converters can connect up to distances of 2 KM with 100 meters of Cat5. The 190C single mode fiber converter can transmit up to distances up to 15 KM.

• Use the MIL-120A and be sure to use the correct UTP cable straight or swap (1-3, 2-6, 3-1, 6-2)

• If the thin-net segment has 10 nodes or less, then the MIL-120A converter will do the trick. Otherwise, you need to use a full repeater like the MIL-4201R (UTP) and MIL-4320M (thin-net) modules. You may also consider one of our MIL-4700 series modular micro-hubs.

• A converter will translate data from one media to another by performing a bit for bit translation. The signal will be re-amplified and squared off. They will also extend "runts" (undersized frames, usually the result of a collision). A repeater, beside re-amplification, will also re-time the data and generate the preamble in ethernet frames. Re-timing removes jitter from the line. Jitter can be a more common problem on coax networks, and that is why the MIL-120A limits the number of nodes to 10 max.