Summary of MicroVAX Communications Controllers

The following table summarizes the features of Digital's MicroVAX 2000 and 
MicroVAX 3100 communications controllers.



MicroVAX 2000 and MicroVAX 3100 Communications Controllers

		DHT32		DST32		DSH32(6)	DSH32

Type		Asynchronous	Synchronous	Asynchronous	Synchronous

Number of Lines	8		1		8		1

Direct Memory	No		No		No		No
Access (DMA)(1)

Maximum Speed	38.4 Kb/s	19.2 Kb/s	38.4 Kb/s	19.2 Kb/s
(consult SPD)(2)

Software 	DECnet-VAX(5),	DECnet-VAX(5), 	DECnet-ULTRIX,	VAX P.S.I.,
Support		DECnet-ULTRIX	VAX P.S.I.,	DECnet-VAX	VMS/SNA,
				VMS/SNA,			DECnet-VAX,
				DECnet ULTRIX,			DECnet ULTRIX,
				ULTRIX WAN 			ULTRIX WAN 
				Device Drivers			Device Drivers

Operating 	VMS, ULTRIX	VMS, ULTRIX	VMS, ULTRIX	VMS, ULTRIX
System Support

MultiCPU 	No		No		No		Yes
Access(3)

Modem 		No		Full		No		Full
Control(4)

Primary Buying	EIA-423-A	Low-cost 	Adds 8 lines 
Reason		asynchronous	connection	and a low-cost 
		communications;	to wide area 	connection to
		adds 8 more	network		wide area network
		lines to 
		MicroVAX 2000 
		system's standard 
		four lines

(1)DMA is the ability to move multicharacter messages between a communication 
   line and CPU memory without interrupting the CPU. This capability yields 
   higher performance.

(2)Actual device speed and throughput depend on current Digital operating 
   system, system configuration, and applications.

(3)MultiCPU Access is the ability to send a message directly to two or more 
   CPUs without routing the message through another CPU.

(4)Modem control refers to the number of signals available to control modem 
   functions on U.S. and European modems. Full modem control includes nine to 
   eleven signals. Limited modem control is five signals. No modem control 
   means only send and receive signals are present for each line.

(5)DECnet-VAX currently supports these devices with certain line and speed 
   configuration restrictions. Refer to SPD 25.03 for more information.

(6)DEC Multicontroller 581.