Asynchronous Serial Communications Programmer's Reference Manual (32022-90052)

24 Chapter1

Introduction

Asynchronous Serial Communications

While the system console is technically an asynchronous serial device,

its functionality, as well as its physical and logical interfaces, are very

different from those discussed in this manual. For more information on

the system console see Managing Peripherals manual.

Non-Hewlett-Packard Devices

Theoretically, any device that conforms to Hewlett-Packard’s

asynchronous protocols and is capable of being physically connected to

the system can be controlled through Asynchronous Serial

Communications. This could include test instruments, data collection

devices, etc. Such devices must be capable of performing XON/XOFF

ﬂow control, and should be conﬁgured as terminal type 18 or printer

type 18. Extreme care must be taken when connecting any

non-supported device.

NOTE

Non-HP devices are not supported. HP is not responsible for

troubleshooting customer problems that involve the use of

non-supported devices

PAD Device Connections

MPE/iX systems are also capable of supporting asynchronous devices

connected through a private or public PAD. While any device normally

supported as an asynchronous device can be connected in this manner,

there are certain differences in how they are conﬁgured, and in how

they react to various programmatic controls. For information on

conﬁguring PAD connections or systems managed by an OpenView

DTC workstation, see Using the OpenView DTC Manager manual. For

information on conﬁguring PAD connections on host-based systems, see

Conﬁguring and Managing Host-Based X.25 Links manual. Refer to

Chapter 7, “Programming for PAD, DTC Telnet, Telnet/iX Server, and

VT Devices,” of this manual for more information on PAD connections

and programmatic control.

Telnet

The Telnet protocol provides a standard virtual terminal connection

between the HP 3000 and other HP and non-HP systems. MPE/iX

Telnet connections can be made using one of two solutions: 1) via a

direct HP 3000 implementation called “Telnet/iX” which enables users

to have direct access to, or from an HP 3000 using the Telnet protocol.

This product provides both inbound and outbound Telnet connections

using only HP 3000 resident code. 2) via a Datacommunications and

Terminal Controller (DTC) with a Telnet Access Card (herein referred

to as “DTC Telnet”) which provides only inbound Telnet access to an

HP 3000 through a DTC.