Xylem H-4271 - Manual (Page 13)

2.6 Words of Caution
Successful operation can depend on may factors. Multipath, interference and other site specific
problems can make a radio link unworkable. After installation it is highly recommended to test
the link with the Digi’s X-CTU software utility as explained at the end of this chapter. When
multipath conditions exist simply moving one of the antennas a few feet can make a difference.
In general, use low-loss antenna cable, a high quality antenna and mount the antenna as high
above the earth as possible. 900MHz signals require line-of-sight operation and generally will
not propagate around hills or other large obstructions. A wise system integrator will perform a
preliminary site test to see if the link is workable before permanently installing the equipment.
! Even though the H-4271 operates in a low power mode, the transmitter requires 500mA for
short bursts. Make certain your wiring and battery is capable of supplying sufficient current .
! Keep the antenna cable as short as possible.
! Use low-loss antenna cable
! Install a lightening protection device on the antenna cable
! Connect the modem case to a good earth ground
! Protect any exposed antenna connectors from water and corrosion
2.7 Modem Configuration
The following sections document the modem configurations for several specific applications
available from the factory. These settings can be checked or changed with either “AT”
commands or with use of Digi’s X-CTU Windows-based application as described in Chapter 1.
General configuration notes:
! All radios are setup for 9600 baud
! Set the destination address for all radios to the same unique value (Design Analysis
Associates uses: ATDT=DCBA)
! A master configured for Sleep&Sniff is workable with a slave which is not configured with
Sleep&Sniff (the slave ignores the beacon)
! Set ATCS=1 in the slave radios so RTS will awaken the H-4191 module when used
! Set ATCD=0 so the RxDat LED will work
! The ATRO and ATMD commands have different settings between the 9Xstream and
9XTend models
H-4271
Installation And Maintenance 2-3