SFF-8472 A0h register map
The serial ID block at two-wire address A0h is the identity of every SFP-class module. This page lists all 128 defined bytes with their bit fields, units and coded values, compiled against SFF-8472 Rev 12.4 (fields that appeared in a later revision are marked rev). Use it next to the EEPROM editor; narrative explanations live in SFF-8472, Compliance codes and Vendor fields.
Legend: rsvd = reserved (write 0, ignore on read) · vendor = vendor specific · bit numbering 7 (MSB) … 0 (LSB).
Base ID — bytes 0–63
| Byte | Field | Contents |
|---|
| 0 | Identifier | SFF-8024 Table 4-1: 00h unknown · 01h GBIC · 02h soldered · 03h SFP/SFP+/SFP28 · 0Bh DWDM-SFP (non-8472) |
| 1 | Extended identifier | 00h GBIC not specified · 01h–03h GBIC MOD_DEF 1–3 · 04h GBIC/SFP defined by two-wire ID only (standard for SFP) · 05h–07h MOD_DEF 5–7 |
| 2 | Connector | SFF-8024 Table 4-3: 01h SC · 07h LC · 0Bh optical pigtail · 0Ch MPO 1×12 · 21h copper pigtail · 22h RJ45 · 23h no separable connector (DAC/AOC) |
| 3 | Transceiver compliance | bit 7 10GBASE-ER · 6 10GBASE-LRM · 5 10GBASE-LR · 4 10GBASE-SR · 3 IB 1X SX · 2 IB 1X LX · 1 IB 1X copper active · 0 IB 1X copper passive |
| 4 | Transceiver compliance | 7 ESCON MMF 1310 nm LED · 6 ESCON SMF 1310 nm laser · 5 OC-192 short reach · 4 SONET reach specifier bit 1 · 3 SONET reach specifier bit 2 · 2 OC-48 long · 1 OC-48 intermediate · 0 OC-48 short |
| 5 | Transceiver compliance | 7 rsvd · 6 OC-12 SM long · 5 OC-12 SM intermediate · 4 OC-12 short · 3 rsvd · 2 OC-3 SM long · 1 OC-3 SM intermediate · 0 OC-3 short |
| 6 | Transceiver compliance | 7 BASE-PX · 6 BASE-BX10 · 5 100BASE-FX · 4 100BASE-LX/LX10 · 3 1000BASE-T · 2 1000BASE-CX · 1 1000BASE-LX · 0 1000BASE-SX |
| 7 | FC link length / technology | 7 very long distance (V) · 6 short (S) · 5 intermediate (I) · 4 long (L) · 3 medium (M) · 2 rsvd · 1 shortwave laser, linear Rx (SA) · 0 longwave laser (LC) |
| 8 | FC technology / cable | 7 electrical inter-enclosure (EL) · 6 shortwave laser w/o OFC (SN) · 5 shortwave laser with OFC (SL) · 4 longwave laser (LL) · 3 active cable · 2 passive cable · 1–0 rsvd |
| 9 | FC transmission media | 7 twin axial (TW) · 6 twisted pair (TP) · 5 miniature coax (MI) · 4 video coax (TV) · 3 multimode 62.5 µm (M6) · 2 multimode 50 µm (M5, M5E) · 1 rsvd · 0 single mode (SM) |
| 10 | FC speed | 7 1200 MB/s · 6 800 MB/s · 5 1600 MB/s · 4 400 MB/s · 3 3200 MB/s · 2 200 MB/s · 1 see byte 62 · 0 100 MB/s |
| 11 | Encoding | SFF-8024 Table 4-2 (SFP column): 00h unspecified · 01h 8B/10B · 02h 4B/5B · 03h NRZ · 04h Manchester · 05h SONET scrambled · 06h 64B/66B · 07h 256B/257B · 08h PAM4 |
| 12 | Nominal signalling rate | units of 100 Mb/s (0Dh = 1.3 Gb/s, 67h = 10.3 Gb/s); FFh = rate ≥ 25.4 Gb/s, see byte 66 |
| 13 | Rate identifier | 00h unspecified · 01h SFF-8079 (4/2/1G rate select) · 02h SFF-8431 Rx rate select only · 04h SFF-8431 Tx rate select only · 06h SFF-8431 independent Rx & Tx · 08h FC-PI-5 (16/8/4G Rx only) · 0Ah FC-PI-5 independent Rx & Tx · 0Ch FC-PI-6 (32/16/8G independent) · 0Eh 10/8G Rx & Tx rate select · 10h FC-PI-7 (64/32/16G independent) · 20h rate select by PMD per A2h byte 36 rev 12.x — Rate select |
| 14 | Length SMF | km; 00h = not supported / not SMF; FFh = > 254 km |
| 15 | Length SMF | units of 100 m; FFh = > 25.4 km |
| 16 | Length 50 µm OM2 | units of 10 m |
| 17 | Length 62.5 µm OM1 | units of 10 m |
| 18 | Length OM4 or copper | optical: OM4 in units of 10 m; copper/DAC: length in metres (FFh = > 254 m) |
| 19 | Length OM3 | units of 10 m |
| 20–35 | Vendor name | 16 ASCII, left-justified, space (20h) padded |
| 36 | Extended specification compliance | SFF-8024 Table 4-4 single value (02h 25GBASE-SR, 03h 25GBASE-LR, 0Bh–0Dh 25G CR L/S/N …) — see SFF-8024 |
| 37–39 | Vendor OUI | IEEE company identifier, MSB first; 00-00-00 = unspecified |
| 40–55 | Vendor PN | 16 ASCII |
| 56–59 | Vendor rev | 4 ASCII (spaces if none) |
| 60–61 | Wavelength | optical: nm, 16-bit unsigned (60 = MSB), e.g. 051Eh = 1310 nm · passive cable: byte 60 bit 0 SFF-8431 Appendix E compliant, bit 1 FC-PI-4 Appendix H compliant, byte 61 rsvd · active cable: byte 60 bit 0 SFF-8431 App. E, bit 1 FC-PI-4 App. H, bit 2 SFF-8431 limiting, bit 3 FC-PI-4 limiting, byte 61 rsvd |
| 62 | FC speed 2 | bit 0 64GFC · bit 1 128GFC rev 12.3 · 7–2 rsvd |
| 63 | CC_BASE | (Σ bytes 0–62) mod 256 — Checksums |
Extended ID — bytes 64–95
| Byte | Field | Contents |
|---|
| 64 | Options | 7 rsvd · 6 rsvd · 5 high power level declaration — level 3, up to 2.0 W rev 12.3 · 4 paging implemented (A2h byte 127 active) · 3 retimer/CDR present · 2 cooled transmitter · 1 power level 2 (≤ 1.5 W); 0 = level 1 (≤ 1.0 W) · 0 linear receiver output |
| 65 | Options | 7 receiver decision threshold implemented · 6 tunable transmitter (SFF-8690) · 5 RATE_SELECT implemented · 4 TX_DISABLE implemented · 3 TX_FAULT implemented · 2 LOS inverted (signal-detect polarity) · 1 LOS implemented · 0 rsvd |
| 66 | Signalling rate max | if byte 12 ≠ FFh: upper margin above nominal, % · if byte 12 = FFh: nominal rate in units of 250 Mb/s (67h = 25.75 Gb/s) |
| 67 | Signalling rate min | lower margin below nominal, % (with byte 12 = FFh: ± margin) |
| 68–83 | Vendor SN | 16 ASCII |
| 84–91 | Date code | ASCII YYMMDD + 2-character lot code (spaces if none) |
| 92 | Diagnostic monitoring type | 7 rsvd (legacy diagnostics) · 6 DDM implemented · 5 internally calibrated · 4 externally calibrated · 3 Rx power measurement: 1 = average, 0 = OMA · 2 address change required before A2h access · 1–0 rsvd |
| 93 | Enhanced options | 7 alarm/warning flags implemented (A2h 112–117) · 6 soft TX_DISABLE control & monitoring · 5 soft TX_FAULT monitoring · 4 soft RX_LOS monitoring · 3 soft RATE_SELECT control & monitoring · 2 application select per SFF-8079 · 1 soft rate select per SFF-8431 · 0 rsvd |
| 94 | SFF-8472 compliance | 00h unspecified · 01h Rev 9.3 · 02h Rev 9.5 · 03h Rev 10.2 · 04h Rev 10.4 · 05h Rev 11.0 · 06h Rev 11.3 · 07h Rev 11.4 · 08h Rev 12.0 · 09h Rev 12.4 — Specification revisions |
| 95 | CC_EXT | (Σ bytes 64–94) mod 256 |
Vendor specific and reserved — bytes 96–255
| Byte | Field | Contents |
|---|
| 96–127 | Vendor specific | free for the manufacturer: configuration, signatures, production data; never checksummed |
| 128–255 | Reserved | reserved for SFF-8079 application-select tables; normally FFh or 00h |
Reading a few common identities
| Module | Bytes 0/1/2 | 3–10 | 11 | 12 | 60–61 | 36 | 64/65 | 92 | 94 |
|---|
| 1000BASE-SX | 03 04 07 | 00 00 00 01 00 00 00 00 | 01 | 0D | 0352 (850) | 00 | 00 / 1A | 68 | 04 |
| 10GBASE-LR | 03 04 07 | 20 00 00 00 00 00 00 00 | 06 | 67 | 051E (1310) | 00 | 00 / 1A | 68 | 05 |
| 25GBASE-SR | 03 04 07 | 00 00 00 00 00 00 00 00 | 06 | FF (66 = 67h) | 0352 | 02 | 08 / 1A | 68 | 08 |
| 10G passive DAC 3 m | 03 04 23 | 00 00 00 00 00 04 00 00 | 06 | 67 | 0100 (byte 60 = 01h App. E) | 00 | 00 / 00 | 00 | 05 |
| 1000BASE-T copper | 03 04 22 | 00 00 00 08 00 00 00 00 | 01 | 0D | 0000 | 00 | 00 / 12 | 00 | 04 |
Values shown are typical, with byte 18 = 03h on the DAC (3 m), byte 65 = 1Ah meaning TX_DISABLE, TX_FAULT and LOS implemented, and 92 = 68h meaning DDM implemented, internally calibrated, average Rx power.
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