In addition, the digital diagnostics monitoring (DDM) function is common in many modern SFP/SFP+ receivers, as defined in the SFF-8472 MSA specification. “D” in GLC-LH-SMD represents the DDM function according to the industry standard MSA SFF-8472. The SFF-8472 added a DDM interface and sketched that the DDM interface is an extension of the serial identification interface defined in the GBIC specification as well as the MSA SFP. SFP/SFP+ receivers also include a management interface (I2C), programmable write memory (EEPROM) with electrical erasure and optional digital diagnostics (DDM, also known as Digital Optical Monitoring or DOM). The EEPROM storage space is defined in the MSA and contains information describing the capabilities of the transceiver, standard interfaces (e..B g. SX, LX, EX, ZX…), manufacturer data and other data. The host system can access this data through the I2C interface, as well as the status of optional DDM functions. Both optical transceiver devices are “standardized” by Multi-Source Agreements (MSAs) and Small Form-Factor Pluggable,Enhanced (SFP+)[ii]. These documents define rigorously sufficient properties of an optical transceiver to enable system providers (e.g.

B Ethernet switch, routers and media converters) to implant ports on their devices so that the connectable optical transceivers (SFP or SFP+) compliant with the MSA work properly by each provider. In other words, transceivers can be purchased by one of the different free market sources like FluxLight. It is true that some system vendors have attempted to undermine the standardization value of SFP MSA or SFP+ MSA. The most common pattern is to write unique code to a part of the indefinite memory in the EEPROM of each SFP/SFP+. When the transceiver is inserted into the host switch, its EEPROM is read and if the code is “fake”, the module is rejected as “incompatible”. But fiber doors can. At present, FS.COM offers a complete brand-compatible transceiver solution, which can meet the requirements of Cisco, HP, Juniper, NETGEAR, Brocade, etc. The SFP-MSA defines a memory assignment of 256 bytes in an EEPROM that describes the transceiver capabilities, standard interfaces, manufacturer, and other information accessible through an I²C serial interface at 8-bit address 1010000X (A0h). .