Editing Small Form-factor Pluggable (section)

==Signals==
[[File:SFP-front-RX-TX.jpg|thumb|right|Front view of SFP module with integrated [[LC connector]] indicating transmission direction of the two optical connectors]]
[[File:SFP internal.jpg|thumb|Disassembled OC-3 SFP. The top, metal canister is the transmitting laser diode, the bottom, plastic canister is the receiving photo diode.]]

SFP transceivers are ''right-handed'': From their perspective, they transmit on the right and receive on the left. When looking into the optical connectors, transmission comes from the left and reception is on the right.<ref>{{cite web |url=https://www.cisco.com/c/en/us/td/docs/interfaces_modules/transceiver_modules/installation/note/78_15160.html |title=Cisco SFP and SFP+ Transceiver Module Installation Notes |publisher=[[Cisco Systems]] |access-date=2021-06-26}}</ref>

The SFP transceiver contains a [[printed circuit board]] with an [[edge connector]] with 20 pads that mate on the rear with the SFP electrical connector in the host system. The QSFP has 38 pads including 4 high-speed transmit data pairs and 4 high-speed receive data pairs.<ref name="inf8438"/><ref name="sff8436"/>

{| {{table}}

|+SFP electrical pin-out<ref name="sfpmsa"/>
|-
! Pad
! Name
! Function
|-
| 1
| VeeT
| Transmitter ground
|-
| 2
| Tx_Fault
| Transmitter fault indication
|-
| 3
| Tx_Disable
| Optical output disabled when high
|-
| 4
| SDA
| 2-wire serial interface data line (using the [[CMOS]] [[EEPROM]] protocol defined for the [[ATMEL]] AT24C01A/02/04 family<ref>INF-8074i B4</ref>)
|-
| 5
| SCL
| 2-wire serial interface clock
|-
| 6
| Mod_ABS
| Module absent, connection to VeeT or VeeR in the module indicates module presence to host
|-
| 7
| RS0
| Rate select 0
|-
| 8
| Rx_LOS
| Receiver loss of signal indication
|-
| 9
| RS1
| Rate select 1
|-
| 10
| VeeR
| Receiver ground
|-
| 11
| VeeR
| Receiver ground
|-
| 12
| RD-
| Inverted received data
|-
| 13
| RD+
| Received data
|-
| 14
| VeeR
| Receiver ground
|-
| 15
| VccR
| Receiver power (3.3&nbsp;V, max. 300&nbsp;mA)
|-
| 16
| VccT
| Transmitter power (3.3&nbsp;V, max. 300&nbsp;mA)
|-
| 17
| VeeT
| Transmitter ground
|-
| 18
| TD+
| Transmit data
|-
| 19
| TD-
| Inverted transmit data
|-
| 20
| VeeT
| Transmitter ground
|-
|}

{| {{table}}

|+QSFP electrical pin-out<ref name="inf8438"/>
|-

! Pad
! Name
! Function
|-
|1
|GND
|Ground
|-
|2
|Tx2n
|Transmitter inverted data input
|-
|3
|Tx2p
|Transmitter non-inverted data input
|-
|4
|GND
|Ground
|-
|5
|Tx4n
|Transmitter inverted data input
|-
|6
|Tx4p
|Transmitter non-inverted data input
|-
|7
|GND
|Ground
|-
|8
|ModSelL
|Module select
|-
|9
|ResetL
|Module reset
|-
|10
|Vcc-Rx
| +3.3&nbsp;V receiver power supply
|-
|11
|SCL
|Two-wire serial interface clock
|-
|12
|SDA
|Two-wire serial interface data
|-
|13
|GND
|Ground
|-
|14
|Rx3p
|Receiver non-inverted data output
|-
|15
|Rx3n
|Receiver inverted data output
|-
|16
|GND
|Ground
|-
|17
|Rx1p
|Receiver non-inverted data output
|-
|18
|Rx1n
|Receiver inverted data output
|-
|19
|GND
|Ground
|-
|20
|GND
|Ground
|-
|21
|Rx2n
|Receiver inverted data output
|-
|22
|Rx2p
|Receiver non-inverted data output
|-
|23
|GND
|Ground
|-
|24
|Rx4n
|Receiver inverted data output
|-
|25
|Rx4p
|Receiver non-inverted data output
|-
|26
|GND
|Ground
|-
|27
|ModPrsL
|Module present
|-
|28
|IntL
|Interrupt
|-
|29
|Vcc-Tx
| +3.3&nbsp;V transmitter power supply
|-
|30
|Vcc1
| +3.3&nbsp;V power supply
|-
|31
|LPMode
|Low power mode
|-
|32
|GND
|Ground
|-
|33
|Tx3p
|Transmitter non-inverted data input
|-
|34
|Tx3n
|Transmitter inverted data input
|-
|35
|GND
|Ground
|-
|36
|Tx1p
|Transmitter non-inverted data input
|-
|37
|Tx1n
|Transmitter inverted data input
|-
|38
|GND
|Ground
|}