View source for CXY08 8-Line Asynchronous Multiplexer

[[Image:M3119-YA.jpg|300px|right|thumb|M3119-YA Multiplexer Card]]

The '''CXY08 8-Line Asynchronous Multiplexer''' is a later [[QBUS]] equivalent to the [[UNIBUS]] [[DH11 asynchronous serial line interface|DH11]] (it is a replacement for the [[DHQ11 asynchronous serial line interface|DHQ11]]). It provided 8 [[EIA RS-232 serial line interface|RS-232]] [[asynchronous serial line]]s. Output used [[Direct Memory Access|DMA]] (with each line having its own [[buffer]] [[pointer]] and count); input used a 256-character [[First-In First-Out buffer|FIFO buffer]].

Like the DHQ11, it can be set (via a switch) to exactly emulate either a [[DHV11 asynchronous serial line interface|DHV11]] or [[DHU11 asynchronous serial line interface|DHU11]]. It has full [[modem]] control.

==Implementation==

Physically, the CXY08 consisted of a single [[DEC card form factor|quad]] card, the M3119-YA. It connected to a pair of BC19N-12 distribution cable assemblies (4 lines each); each BC19N ends in four male [[EIA RS-232 serial line interface#Connectors|DB-25 connectors]] (DB-25P).

==Device registers==

The [[register]]s will depend on whether it is emulating a DHV11 or DHU11.

==Further reading==

* ''CXY08 User's Guide'' (EK-CXY08-UG) - not available online
* ''CXY08 Technical Manual'' (EK-CXY08-TM) - not available online

==External links==

* [http://vaxhaven.com/images/f/fe/EK-CXY08-IN-001.pdf CXY08-AF 8-Line Asynchronous Multiplexer Option Installation Guide] (EK-CXY08-IN-001)
* [http://bitsavers.org/pdf/dec/qbus/MP02382_CXY08_sch_Mar87.pdf CXY08 Field Maintenance Print Set] (MP-02382)

[[Category: QBUS Asynchronous Serial Interfaces]]