Patent ID: 8159956

Claim:
A serial communications device, comprising: a first module coupled to a second module via a serial cable, wherein each respective module of the first and second modules comprise: a controller configured to obtain digital diagnostic data representative of operational characteristics of the respective module; memory configured to store the digital diagnostic data; a first interface configured to allow an external host to request the digital diagnostic data; a second interface distinct and separate from the first interface, the second interface configured to serially communicate data between the first module and the second module via the serial cable; and a signal controller configured to encode the digital diagnostic data onto a serial data signal for transmission via the first interface or the second interface by adjusting signal levels of the serial data signal while preserving original data in the serial data signal, wherein encoding the digital diagnostic data onto the serial data signal while preserving the original data in the serial data signal includes: serializing the digital diagnostic data; determining a series of signal levels for the serialized digital diagnostic data based on a signal encoding map; and adjusting signal levels for the serial data signal based on the determined series of signal levels.