Chapter 1: Understanding HDSL and the Express L768/L1.5
THE EXPRESS L768/L1.5
The Express L768/L1.5 is a standalone device that links two Local Area Net- works (LANs) using a high-speed DSL two-wire or four-wire line. The Express L768 has a two-wire interface and operates up to 768 kbits per second. The Ex- press L1.5 has a four-wire interface and operates up to 1.536 Mbits per second. The Express L1.5 is compatible with the Express L768 in a two-wire mode if the rate is 768K and below.
See Figure 1-1 for an illustration of the Express L768/L1.5. The 10BaseT con- nector operates at 10 Mbits per second half duplex and accepts standard eth- ernet packets encapsulated using IEEE 802.3 or Ethernet II (DIX). Because the 10BaseT is a four-wire interface, a crossover switch permits the user to connect to either a hub-concentrator or network interface card without the need for special cabling. The maintenance port can connect to any asynchronous termi- nal emulating a VT 100 terminal for configuration.
| TX/RX | LOOP | LINK | PWR |
LI | | |
| | |
| | | |
L768 | | | | |
EXPRESS | | | | |
| | | TEST | LINE |
| | | |
L768
| TX/RX | LOOP1 | LOOP2 | PWR |
LI | | |
| | |
| | | |
L1.5 | | | | |
EXPRESS | | | | |
| | | TEST | LINE |
| | | |
L1.5
Figure 1-1
Express L768/L1.5
4 | Express L768/L1.5 User Manual | 61202192L1-1 |
