The QSFP-DD MSA is a multi-company industry group. The QSFP-DD MSA has defined a high-density 8-channel (8x) module, cage, and connector system. QSFP-DD supports up to 400 Gb/s in aggregate over an 8 x 50 Gb/s electrical interface. QSFP-DD MSA recommended three duplex connectors, MDC connector, CS connector and SN connector. The following paragraph are an introduction to these connectors.
CS Connector
The CS connector is a miniature single-position plug which is characterized by duo cylindrical, spring loaded butting ferrule(s) of a 1.25 mm typical diameter, and a push-pull coupling mechanism. The optical alignment mechanism of the connectors is a rigid bore sleeve or a resilient sleeve. The document also defines the standard interface dimensions of active device receptacles for dual CS connectors. The receptacles are used to retain the connector plugs and mechanically maintain the optical datum target of the plugs at a defined position within the receptacle housings.
SN™ Connector
The SN™ connector is a miniature single-position plug which is characterized by duo cylindrical, spring loaded butting ferrule(s) of a 1.25 mm typical diameter, and a push-pull coupling mechanism. The optical alignment mechanism of the connectors is a rigid bore sleeve or a resilient sleeve. The document defines the standard interface dimensions of active device receptacles for SN™ connector. The receptacles are used to retain the connector plugs and mechanically maintain the optical datum target of the plugs at a defined position within the receptacle housings.
MDC Connector
The MDC connector is a very small form factor optical connector designed to provide separate two-fiber connections into a OSFP or QSFP-DD module and separate two-fiber connections into a SFP-DD module. A push-pull boot allows for simple insertion (and removal) of the MDC connectors to (and from) the receptacles. The MDC connector contains 1.25 mm diameter ferrules and will be installed on 2.0 mm OD (or less) optical cables.
Reference: QSFP-DD MSA
