Dear Colleagues,
During the final proof-reading & preparation for publication of IEEE Std 802.3cm-2020, Mr Pete Anslow, who was contracted by IEEE-SA for this task, noted that the IEC 61754-7-4 draft standard referenced in subclause 138.10.3.4 'MDI requirements for 400GBASE-SR8' had progressed more slowly than we had expected and was not yet in a state where it could be referenced. As a result the IEEE P802.3cm leadership and IEEE P802.3cm connecter expert participants worked together to find the precise TIA references that would match the not-yet-final IEC references. As a result the IEC 61754-7-4 draft standard reference has been replaced with a reference to ANSI/TIA-604-18-A.
As a result I've been contacted by an individual that informed me this has resulted in confusion with respect to the connector being flat or angled.
I wanted to clarify that while the description for 'interface 7-4-10' defined in the IEC 61754-7-4 draft standard "MPO active device receptacle, flat interface for 16 fibers" uses the term 'flat' and the ANSI/TIA-604-18-A equivalent "FOCIS 18 R-1x16-1-0-1-2-0" uses a series of numbers instead, it is in fact an MPO connector as an active device receptacle, with flat interface for 16 fibers. [Specifically: FOCIS 18 R - m x n - k - a - c - t - o, where a = 0 designates contact angle of 0°, or a flat contact angle for the receptacle].
Additionally, while the description for 'interface 7-4-5' defined in the IEC 61754-7-4 draft standard "MPO female plug, flat interface for 16 fibers" uses the term 'flat' and the ANSI/TIA-604-18-A equivalent "FOCIS 18 P-1x16-1-0-2-2-0" uses a series of numbers instead, it is in fact an MPO female plug connector, flat interface for 16 fibers. [Specifically: FOCIS 18 P - m x n - k - a - c - t - o, where a = 0 designates contact angle of 0°, or a flat contact angle for the plug].
As a result the MDI specified in IEEE Std 802.3cm-2020 subclause 138.10.3.4 remains an MPO connector with a flat (contact angle of 0°) interface.
Furthermore, clause 138.10.3.4 "MDI requirements for 400GBASE-SR8" continues to refer to Fig. 138-8, which explicitly refers to plugs and receptacles with “a flat interface,” for both option A for a dual-row twelve-fiber interface, and for option B for a single-row sixteen-fiber interface.
