Teledyne 4220 installation and operation guide Options and Accessories, 4200T Modem, How it Works

4220 Flow Meter

Section 5 Options and Accessories

This section describes accessories available for use with 4200 Series Flow Meters. There are two groups of accessories. One group of options you can use with any of the 4200 Series. The other group are accessories for a specific type of level sensing and can only be used with one flow meter of the series. This section covers the accessories that are usable with any 4200 Series Flow Meter. Application-specific options are covered in the Instal- lation sections of each type of flow meter.

Teledyne Isco offers the following options for use with all 4200 series flow meters:

•4200T Modems

•4-20 mA Outputs (Internal and External)

•Model 674 Tipping Bucket Rain Gauge

•Flowlink® Software (used with the modem or a laptop computer)

•Parameter Probes - Temperature, pH (acidity/alkalinity) and D.O. (dissolved oxygen)

•Mechanical Totalizer

•High-Low Alarm Relay Box

•YSI 600 Multi-Parameter Sonde

5.1 4200T Modem

The 4-20 mA Output Interface, alarm box, rain gauge, and parameter probes are options you can field-install any time. The modems require factory modification to the flow meter, and you should specify these options when you order. If you want to add any of these later, you will need to return the flow meter to the factory.

The 4200T Modem is a circuit board installed inside the flow meter that transmits flow meter data over standard telephone lines. The modem also makes it possible for the flow meter to receive data from compatible equipment at the other end of the phone line. Modems allow digital equipment to talk and listen to other remotely-located digital equipment over telephone lines.

5.1.1 How it Works	The analog phone system cannot transmit digital signals
	through repeaters; digital machines cannot communicate
	directly over phone lines. Modems convert the data into tones
	and transmit them over phone lines. The equipment on the other
	end of the line answers with tones through its modem. The first
	modem converts these tones back to digital data and interprets
	it. The 4200T Modem is full duplex and works in the auto-answer

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