The Physical Link

ASIM team
LIP6 Laboratory
Paris, France

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The Physical Link

The physical media is a point-to-point, full duplex, high speed serial link. It's a single wire containing two coaxial cables, one per direction, as shown on the figure 2. The throughput of the link is 1 Gbit/s in each direction.

**Figure 2:** IEEE 1355/HSL Physical Link
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The communication is asynchronous, emitter sends data at its own speed and the receiver recovers both emitter's clock and data. This technology avoids skew problems. The bytes are encoded as shown on the figure 3.

**Figure 3:** Codage des symboles 12 bits sur HSL
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Since each byte requires 12 bits on the link, the throughput on the link is about 80 MB/s. (1 Gbit/s / 12 bit/byte = 80 MB/s)

The maximum length on coaxial cables is about 5 meters. HSL can also be used on optic fiber (in which case the maximum link length is about 70 meters), but this requires external transceivers, and is not implemented on SmartHSL.

Next: The Serialization/Deserialization Operator Up: Introduction to the IEEE 1355 Previous: Introduction to the IEEE 1355