Winsock/Telnet Communication ActiveX for VB and
VC++
The EasyCom ActiveX control is a Winsock/Telnet
communication component. It is intended for VB and VC++
developers to easily add communication capabilities to their
applications. Examples of such communication capabilities might
include handling and configuration of remote network equipments and
servers, and getting information on such systems.
EasyCom vs.
scripting in terminal emulators
There is a couple
of advantages about using EasyCom in VB or VC++ rather than using
terminal emulators built-in scripting tools. First, you get more
control on the running conversation : for instance, when reading,
EasyCom affords easily detecting different possible answers from
the remote system. Second, you can easily get the characters
received and handle and process them as required. See the VB
example attached for an example of this.
Services
Each instance of
EasyCom handles a connection that can be used for reading and
writing. The Read method can wait until one of the strings
expected by the calling program is received, and give back control
when this (or a time-out) happens.
Errors are
handled through error messages that are displayed for a duration
that you specify, thus affording working with absolutely no user
intervention. But if you made another choice, you can also give
user feedback using a “terminal view” window to display the
characters exchanged. For even more user control, this window
includes a Cancel button that affords prematurely terminating the
connection.
Last, you can
specify that you are not waiting for any string to arrive from the
remote computer and be notified through an event if such a string
arrives.
Communication
layers supported
EasyCom affords
working with several distinct underlying communication layers, but
the interface is the same whatever the layer. The difference
resides only in the string that you pass to the Open method, and
that contains all of the configuration data for the layer :
1.
TCP/IP is implemented through the use of the Windows sockets
version 2.0. A minimal Telnet emulation is also included. This
minimal emulation mainly denies whatever service request is done
by the remote computer and hides the Telnet protocol characters
exchanged from the component's Read routine.
2.
Asynchronous communications are implemented through the use of
Mscomm32.ocx, a freely redistributable Microsoft component. The
Mscomm32.ocx option makes the assumption that you are connected to
a PAD asynchronous equipment using the ITU-TT X3 recommendation
(this equipment says "COM" or "ENGAGED" when
the conversation is established, and says "LIB" or
"CLR" when it is freed).
Legacy X25 and
Wincom communication layers
The following
layers are not included with the base release of the product but
can be provided if required :
3.
X25. The software can run on a machine containing a Prima Atlantis
X25 board (Windows 95 or Windows NT), or on a client computer
(Windows 95) using the Atlantis Gateway.
4.
Wincom. Wincom is a Terminal Emulator from Icom informatique, offering
TCP/IP, asynchronous and X25 communications. The versions
supported by EasyCom are V4.2 (32 bits) and Wincom VT320 (16
bits). |
