User's Manual

COMPANY CONFIDENTIAL
RF-TWACS Based AMR System DCSI CUSTOMER PRODUCT SPECIFICATION
May 30, 2003 Application Notes – Rev. 1 6
either a pulser or dial encoder. The RMTR is external to the gas or water meters, and for
adequate radio coverage must be mounted elevated above the ground, possibly on a wall.
Product Related Terms
CCE, Central Communication Equipment. Also referred to as the “Master Station”, the
current model sold to customers is called TWACS Net Server (TNS).
EMA, Electronic Metering Assembly. This can be viewed as either the traditional
“transponder module” or merely as the function in a consolidated assembly that serves as
the TWACS gateway.
EMT-3C-MP, Electric Meter Transceiver Multiport. Also called the EMA, Centron MP,
RCE or transponder.
EMTR, Electric Meter TRransceiver. This unit serves as the RF gateway between the
RMTR and the EMA. This unit continually scans channels, listening for communication
from an RMTR.
HHTR, Hand Held TRansceiver. This hand-held test tool is used to monitor RF traffic,
force link-assignments, as well as facilitate installations and change-outs.
IED, Intelligent End Device. This is an IEEE term. The end device in this case is a
metering device. It may or may not have much intelligence. If the meter is a solid state
meter, or some other metering device that supports two-way electronic communication,
such a device could be termed an “Intelligent End Device.”
RCE, Remote Communication Equipment. Historically known as the “Transponder”, the
RF project affects 3 different types of Remote Communication Equipment: the EMA,
EMTR and the RMTR. If any one of them now had to be called a “transponder” it should
be the EMA since it serves as the TWACS gateway. All of them can still be considered
RCE’s. Transponders are two-way powerline devices while transceivers are two-way
radio devices.
RMTR, Remote Meter TRansceiver. A module separate and distinct from the gas or
water meter that contains a connecting cable, microprocessor, RF circuitry, battery, and
antenna. It normally sleeps, and occasionally wakes to establish an RF link with an
EMTR. It maintains or obtains meter readings and conveys them to the EMTR.
SCE, Substation Communication Equipment. Also known as the “Substation”, the
current model sold to customers is based on the “93-CRU.”
Communication Related Terms
Channel, The selected RF band (902 to 928 MHz) gives opportunity for 79 channels
within the band. The DCSI RF TWACS system makes use of 50 channels. FCC limits the
amount of energy that can be emitted in a given channel for a certain length of time. The
transceiver design has one antenna that the transmitter and receiver portions of the circuit