ADS Environmental Services Model 3600 530002 A2 - Manual (Page 22)

Hardware 2-7
External Modem Unit
An alternative way to communicate via a telephone line is to use an external modem
unit (EMU), which houses the modem outside of the monitor. Two types of EMUs
exist: one with an internal battery power source and one which uses an external power
source. The EMU may be buried in a sidewalk or pavement box at the end of a trench
dug away from the manhole, or the EMU may be bolted to a nearby wall.
The EMU functions similarly to the internal modem and can be programmed to
communicate at various baud rates. For more information on EMU capabilities and
installation, see Chapter 5, “Monitor Installation and Activation.”
EMU

Inside View
Internal Power Source
The internally powered EMU contains a set of alkaline batteries that supply power for
the modem. This internally powered EMU is used in applications where an external
power source is not available. An example of this application is the 3600 flow monitor
that typically collects data at a set time period, such as once per week. The following
standard EMUs provide battery-powered modem communication:
ADS Part Number EMU Model
P/N 106223B United States
P/N 106223C British/German
P/N 106223D French