Finisar AN-2030 Date Code, Diagnostic Monitoring Type, Data Description of field Address

	AN-2030: Digital Diagnostic Monitoring Interface for Optical Transceivers	F i n i s a r
1
2	Date Code
3	The date code is an 8-byte field that contains the vendor’s	date code in ASCII

4characters. The date code is mandatory. The date code shall be in the format specified

5by table 3.7.

6		Table 3.7: Date Code
7
	Data	Description of field
	Address
	84-85	ASCII code, two low order digits of year. (00 = 2000).
	86-87	ASCII code, digits of month (01 = Jan through 12 =
		Dec)
	88-89	ASCII code, day of month (01 - 31)
	90-91	ASCII code, vendor specific lot code, may be blank

8

9Diagnostic Monitoring Type

10“Diagnostic Monitoring Type” is a 1 byte field with 8 single bit indicators describing how

11diagnostic monitoring is implemented in the particular transceiver (see Table 3.8).

12Bit 6, address 92, is set in Finisar ‘7D’ SFPs, 'P' SFPs under the new part numbering

13scheme, and WDM GBICs, indicating that digital diagnostic monitoring has been

14implemented. Received power monitoring, transmitted power monitoring, bias current

15monitoring, supply voltage monitoring and temperature monitoring are all implemented.

16Additionally, alarm and warning thresholds are written as specified in this document at

17locations 00 – 55 on 2 wire serial address 1010001X (A2h) (see Table 3.14).

18If bit 5, “internally calibrated”, is set, the transceiver reports calibrated values directly

19in units of current, power etc. If bit 4, “externally calibrated”, is set, the reported

20values are A/D counts which must be converted to real world units using calibration

21values read using 2 wire serial address 1010001X (A2h) from bytes 55 - 95. Finisar

22transceivers use both calibration types so it is necessary to read bit 5 in order to

23properly interpret transceiver data .

24Bit 3 indicates whether the received power measurement represents average input

25optical power or OMA. If the bit is set, average power is monitored. If it is not, OMA is

26monitored. Finisar transceivers report “average power” and thus bit 3 is set.

27Bit 2 indicates whether or not a special “address change” sequence (described in SFF-

288472) is required. This sequence is NOT required in Finisar modules. Information at

29both 2-wire addresses (A0h and A2h) may be accessed simply by using the appropriate

30address during the 2-wire communication sequence.

31Finisar SFP/GBIC transceivers thus have 0b01111000 written at address 92 if they are

32 internally calibrated, and 0b01011000 written at address 92 if they are externally

33calibrated. Note that internally calibrated devices can be treated as externally calibrated

34devices because the external calibration constants are set to 1 or 0 as appropriate.

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