TX Disable Pin. TX Disable Pin (TX_DIS) is an input pin from the Host, operating with active-high logic. This pin is pulled up in the CFP4. When TX_DIS is asserted, all of the optical outputs inside a CFP4 module shall be turned off. When this pin is de-asserted, transmitters in a CFP4 module shall be turned on according to a predefined TX turned-on process which is defined by the state diagram shown in the “CFP MSA Management Interface Specification”. A maximum time is defined for the transmitter turn-on process. This time is vendor and/or technology specific and the value is stored in a MDIO register. This pin can be optionally configured as Programmable Control 1 Pin after Reset. One MDIO register which defines if the module supports this optional configuration or not is prepared in NVR region. Please refer to Ref.[3] for more details.
