Dynasonics TFXP Series Transit Time Ultrasonic Flow Meter - Manual (Page 113)

This converter is required regardless of the operating system or the type of port on the computer.
The next step up is the infrared connections used on TFXD, PE1, TFXP, HTTP, PE3, TFXM, PE2
transit time meters and MFX series mag probes. Do not confuse this with the general propose
infrared ports built into many computers, calculators, and printers. To make a connection to
UltraLink a dedicated IR device is required.
Finally if the meter is equipped with either the RS-232 or RS-485 capabilities communications can
be established with a direct serial cable connection.
Establishing Communications
The first step in establishing communications with UltraLink is determining what ports are
available on the computer. Older computers using older operating systems may have both RS-232
and USB connections. Newer computers, especially laptop computers, using newer operating
systems usually can only be found with USB ports.
A Word on Converters and Adapters
The words "adapter" and "converter" are often used interchangeably. In fact an
adapter, when used regarding computers, is purely a device that adapts one
physical connection to another. Generally there are no electronics involved and
never software drivers. An example of this would be DB9 to DB25 adapter
pictured at the right.
A converter is an entirely different type of device. Again, in the computer world, whenever one
kind of signal must be changed into another kind of signal a converter is required. The RS-232 to
TTL device needed for the entry level ultrasonic meter is an example of a simple converter. The
device used to convert an RS-232 signal into a signal acceptable to a USB port is more complex
in that it needs a software driver to work correctly.
Standard Serial Ports
RS-232 ports may be physically either DB9 or DB25.
Both of these configurations are acceptable however a DB9 to DB25 adapter may be required.