100 Mbps cabling specifications v1.06 100 Mbps cabling specifications for Intel 82557-based PCI adapters: EtherExpress(TM) PRO/100B - TX EtherExpress(TM) PRO/100B - T4 The EtherExpress PRO adapters have a small, snap-in RJ45 connector. RJ45 cabling is also known as Twisted-pair Ethernet (TPE), Unshielded twisted pair (UTP), and 10BASE-T cabling. The type of cabling you must use depends on the adapter you're using. This document covers the following topics: - EtherExpress PRO/100B - TX adapters - EtherExpress PRO/100B - T4 adapters - Link integrity - Common problems NOTE: For 10 Mbps operation, refer to the 10 Mbps cabling specifications help file. EtherExpress PRO/100B TX adapters ================================= Recommended cables ------------------ The cable must comply with the IEEE 802.3 10BASE-T standard for 2-pair, Category 5, UTP cable. Select a high-quality brand of Category 5 cable from your local supplier. The cable between the computer and the hub must be less than 100 meters long. EtherExpress PRO/100B TX adapters do not support pre-10BASE-T concentrators. Cable and connector pinouts --------------------------- If you need to repair a cable or provide connectors for UTP cable, wire straight through as shown in the following table. Function Pin# Pin# ----------------------------------- TX+ 1 <--------> 1 TX- 2 <--------> 2 RX+ 3 <--------> 3 RX- 6 <--------> 6 Use only four of the eight pins. Pins 1 and 2 must be a pair, and pins 3 and 6 must be a pair. To allow for a straight-through cable, the hub provides an internal transmit/receive crossover function. This means the transmit circuit of the network card is connected to the receive circuit of the hub and vice versa. Pinout for the RJ45 connector ----------------------------- ---------- ------------------------- 1 |-- | 8 |------------ | 2 |-- | 7 |------------ | 3 |-- --- 6 |------------ | 4 |-- | 5 |------------ | 5 |-- | 4 |------------ | 6 |-- --- 3 |------------ | 7 |-- | 2 |------------ | 8 |-- | 1 |------------ | ---------- ------------------------- END TOP Pin name and function: 1 Transmit Data Plus (TD+). The positive signal for the TD differential pair. This signal contains the serial output data stream transmitted onto the network. 2 Transmit Data Minus (TD-). The negative signal for the TD differential pair. This contains the same output as pin 1. 3 Receive Data Plus (RD+). The positive signal for the RD differential pair. This signal contains the serial input data stream received from the network. 4 Not used. 5 Not used. 6 Receive Data Minus (RD-). The negative signal for the RD differential pair. This signal contains the same input as pin 3. 7 Not used. 8 Not used. Connecting two workstations without a hub ----------------------------------------- 100BASE-T uses a star topology. This means a hub or concentrator is in the center of a star, and each workstation or server is connected to this hub. For test purposes, you can directly connect two workstations or a workstation and a server without using a hub. This setup requires a special cable incorporating the crossover function described earlier in this document. The table below shows which wires need to be crossed over. Function Pin# Pin# Function ---------------------------------------------- TX+ 1 <--------> 3 RX+ TX- 2 <--------> 6 RX- RX+ 3 <--------> 1 TX+ RX- 6 <--------> 2 TX- NOTE: This is not an IEEE supported configuration and should be used for test purposes only. EtherExpress PRO/100B T4 adapters ================================= When operating at 100 Mbps, the cable must comply with the IEEE 802.3u 100BASE-T4 specification. Select a high-quality brand of Category 3, 4, or 5 cable from your local supplier. Note that 100BASE-T4 configurations require using all four pairs of wires. The cable between the computer and the hub must be less than 100 meters long. The EtherExpress PRO/100B T4 adapters do not support pre-10BASE-T concentrators. Cable and connector pinouts --------------------------- Unlike TX cabling, T4 cabling does not use separate, dedicated pairs to transmit or receive data. T4 cabling uses all four pairs of wires. Three pairs are used to transmit data, while the fourth pair is used to detect collisions. Pin pairings are as follows: Pins 1 and 2 must be a pair. (TX function) Pins 3 and 6 must be a pair. (RX function) Pins 4 and 5 must be a pair. (Bidirectional) Pins 7 and 8 must be a pair. (Bidirectional) The pinout is as follows: Function Pin# Pin# ----------------------------------- TX D1+ 1 <--------> 1 TX D1- 2 <--------> 2 RX D2+ 3 <--------> 3 BI D3+ 4 <--------> 4 BI D3- 5 <--------> 5 RX D2- 6 <--------> 6 BI D4+ 7 <--------> 7 BI D4- 8 <--------> 8 To allow for a straight-through cable, the hub provides an internal transmit/receive crossover function. This means the transmit circuit of the network card is connected to the receive circuit of the hub and vice versa. Connecting two 100BASE-T4 workstations without a hub ---------------------------------------------------- For test purposes, you can directly connect two workstations or a workstation and a server without using a hub. This setup requires a special cable incorporating the crossover function described earlier in this document. The table below shows which wires need to be crossed over. Function Pin# Pin# Function ---------------------------------------------- TX+ 1 <--------> 3 RX+ TX- 2 <--------> 6 RX- RX+ 3 <--------> 1 TX+ RX- 6 <--------> 2 TX- BI D3+ 4 <--------> 7 BI D4+ BI D3- 5 <--------> 8 BI D4- BI D4+ 7 <--------> 4 BI D3+ BI D4- 8 <--------> 5 BI D3- NOTE: This is not an IEEE supported configuration and should be used for test purposes only. Link integrity ============== There are three LEDs on the EtherExpress PRO/100B T4 and TX adapters: 1. A LNK light for link 2. An ACT light for activity 3. A 100 light which indicates a 100 Mbps connection Refer to your adapter Installation Guide or the "Diagnostic LEDs" Readme file for complete information. Note: The ACT LED indicates read/write activity on the network, not necessarily activity on the adapter. Common problems =============== A hub can't detect a workstation -------------------------------- This is often the result of a crossed wire in the cable or wiring closet. Make sure the wiring is correct. Workstations can't connect to the network ----------------------------------------- Make sure hub port is configured to the correct speed. Also, make sure last line in the NET.CFG file reads: lastdrive=F (for NETX systems) or lastdrive=Z (for VLM systems) Also try resetting the concentrator or hub or turn the power off and on. Polarity problems ----------------- A common problem in 10BASE-T wiring is crossing the positive and negative phases of the transmit or receive signals (for example, crossing pins 1 (TX+) and 2 (TX-)). EtherExpress PRO/100B adapters automatically detect this problem and adjust for it internally. However, it's best to check your wiring and correct this problem if you find it. * Third-party trademarks are the property of their respective owners.