AT&T 2500 series, 7500 series, 7100 series, 7200 series manual Terminal Emulators, PC/PBX or PC/ISDN

8-4DTE CONNECTIONS

____________________________________________________________________________________________________________________________

_

Terminal Emulators

Many host and personal computer manufacturers endorse terminal emulation software that will send data in a format that the destination DTE expects. For example, DEC’s VT100® terminal emulation package, and AT&T’s ATT513 and ATT4410 packages give IBM-compatible PCs the ability to communicate in the same formats as the terminals for which the packages are named. In addition, some data communications packages — like TERRANOVA® — provide IBM-compatible PC users with terminal emulation, file transfer, and scripting capabilities. Ask your computer manufacturers to recommend a communications package for your PC or host.

PC/PBX or PC/ISDN

The PC/PBX and PC/ISDN are both hardware/firmware platforms on which terminal emulation software runs. Both are housed on circuit boards that can be plugged into an IBM XT/AT compatible personal computer. When either of these boards are in place, you can use their respective 3270 emulation or asynchronous communications packages to communicate with a host. Figure 8-1shows how to configure the connection between an IBM mainframe and a personal computer on which the PC/PBX or PC/ISDN platform and 3270 emulation are running.

DCP		P		P	3270C	CLUSTER	FRONT	IBM
	D O		D O			CONTROLLER	END
	C R		C	R	DCP			HOST
							PROCESSOR
PC/PBX	P	T	P	T
			D	P	DMI		COMTEN
			S	O			PROCESSOR
			1	R
				T
BRI	B	P	D	P
		O		O
	R	R	C	R	DCP	3270C
	I		P
		T		T
PC/ISDN
		Figure 8-1.	PC/PBX and PC/ISDN 3270 Emulation Connections

Note that the PC/PBX communicates through a DCP port (known as a digital-line port on the System 75 and Generic 1 communications systems, and as a GPP port on the System 85 and Generic 2 communications systems); while the PC/ISDN uses a BRI port (currently available on the Generic 2 communications system only, but soon to be available on the Generic 1) for the PC connection, but a DCP port (GPP or digital-line port) for the 3270C connection. PC/ISDN sends data over both the BRI B- channels and the D-channel. The Generic 2 system can circuit switch the B-channel data, but cannot process the D-channel X.25 data packets.