SNLA335B september 2019 – may 2023 DS250DF210 , DS250DF230 , DS250DF410 , DS250DF810 , DS280BR810 , DS280BR820 , DS280DF810 , DS280MB810
Link training is an optional Physical Coding Sublayer (PCS) function specified by the IEEE 802.3 Ethernet specification. It is also used by other standards such as PCIe and Fibre Channel. Link training is a state-machine based algorithm that enables two interconnected systems to converge on their respective optimal transmit equalization settings. Typically the switch ASIC (either front-port or backplane) implements the link training function. Signal conditioners such as TI retimers and redrivers are by definition mid-channel devices. In other words, these devices are placed in the middle of the ASIC-to-ASIC link to provide channel reach extension. The level of link training support offered by signal conditioners can be broken down into three categories, as described in Table 4-1.
| LINK TRAINING CATEGORY | DESCRIPTION | TI 25G/28G SigCon PRODUCTS IN CATEGORY |
|---|---|---|
| No link training support | These devices neither implement the link training digital logic nor do they pass through the link training amplitude info | DS250DF810, DS280DF810, DS250DF410, DS250DF210, DS250DF230 |
| Link training pass-through | Highly linear devices such as TI's 25G/28G redrivers will seamlessly pass through the link training amplitude info from one end to the other | DS280BR820., DS280MB810 |
| Full link training support | These devices implement the digital logic required to execute the link training process in accordance with network standards | Not supported by TI retimers or redrivers |