Serial Comm Library
An effective multiport serial board must be able to work with different software packages so that applications such as Remote Access Service, Winfax, and Terminal Emulation, can be used. There are, however, other applications using multiport boards to control external devices that require the development of proprietary software. In this case, an easy-to-use library and powerful debugging tool become critical factors as far as development cost and time are concerned. Different solutions are available, depending on the operating system.
1. DOS
There are no standard APIs defined under DOS, making it necessary to use a different solution, such as direct I/O access, Int14, or proprietary APIs. Since these solutions are incompatible with each other, finding an easy programming solution is a major problem.
2. Windows 3.x
Windows 3.x comes with the Win16 Comm SDK that allows
programmers to access a PC's COM ports. Communication objects
based
on Win16, such as MsCOMM for VB, may also be used to access
COM ports. However, you can only install a maximum of 9
COM ports on the system due to the restrictions imposed
from within the Windows 3.x OS.
3. Windows 2000/NT/95/98/ME
Windows 2000/NT supports 256 COM ports, whereas Windows
95/98/ME supports a maximum of 128 COM ports. Although
the Win32 API, which can access each COM port, is powerful
and versatile, the complexity of the API increases development
costs, forcing programmers to look for easier solutions.
Compared to the complex Win32 API, communication objects
are more popular and much more acceptable. In Microsoft
Visual Basic for example, you may use an MsComm object
to access your COM ports. Third party communication objects,
such as Inprise Delphi compiler, are also available. Although
communication objects are easy to use, performance and
scalability does not seem to satisfy all system developers.
For example, MsComm only supports a maximum of 16
COM ports.
Debugging Tool
During system development, programmers may need to use certain instruments to verify that online communication is working properly. There are two basic solutions available. The hardware solution, i.e., a Stand-Alone Protocol Analyzer and Data Scope machine, is powerful, precise, and sophisticated. The only drawback is its expense. The other alternative is to use a software solution that turns a PC into a Data Scope. You may lose precision and auto-detection, but it is relatively affordable and cost-effective.
API-232/DOS for DOS platforms
API-232/DOS is the standard programming library for all
Moxa products running under DOS. Each function is comprehensive
and easy to use. API-232/DOS provides versatile functions
that cover both basic data transfer as well as the advanced
XModem, YModem, and ZModem file transfer functions. Furthermore,
polling and interrupt style control functions are supported
simultaneously for every aspect of programming style, and
the library is compatible with most popular compilers,
including QBasic, Turbo/Borland C, Microsoft C, Turbo Pascal,
Assembly, and Clipper. The API-232/DOS driver package contains
SCOPE.EXE, which operates similarly to Data Scope, helping
you capture and analyze on-line data communication.
API-232/Win3.x for Windows 3.x
platforms
Although Windows 3.x only supports up to 9 COM ports and
the system scale is relatively limited, it is still an
economical 16-bit GUI system. API-232/Win3.x
helps system developers build systems with fewer than 9
serial ports on a Windows 3.x system. The API is
compatible with 16-bit Borland C and Microsoft Visual C++,
and as with API-232/DOS, API-232/Win3.x is designed
to reduce the amount of maintenance required and helps
lower migrating costs.
PComm Library for Windows 2000/NT/95/98/ME platform
PComm library is the ultimate productivity answer for
system developers. It is easy to use, and provides both
basic and advanced functions, such as file transfer and
callback. PComm library operates in a manner similar to
the API-232/DOS/Win3.x library, and in this way can effectively
reduce the time and cost required to utilize powerful 32-bit
platforms. PComm library is available with PComm Lite,
and works with all popular 32-bit compilers, such as Microsoft
Visual Basic, Microsoft Visual C++, Borland C++, and Inprise
Delphi. Moxa's Data Scope utility provides users with
another powerful and versatile tool. Simply attach
a debugging cable to your PC, install Data Scope
to turn your PC into a Windows based Data
Scope to display and capture on-line data. Data can also
be conveniently
stored for further analysis.
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