User`s guide

LONWORKS Network Connection
The SLTA-10 includes a removable screw terminal connector (Jl) for the twisted pair
LONWORKS network connection. The Jl should be connected as follows:
s!zl
1
Polarity
Insensitive
2
Jl
Models 73351,73352,73353
RS-485
Cable -
Shield
Jl
Model 73354
Attaching the SLTA- 10 Adapter
EIA-232 devices are configured as either Data Circuit-terminating Equipment (DCE)
or as Data Terminal Equipment (DTE). A DCE device connects to a DTE device,
unless a null modem cable is used. Using a null modem cable, a DCE device connects
to a DCE device and a DTE device connects to a DTE device. The SLTA-10 Adapter
is a DCE device.
The standard configuration for a PC/AT EIA-282 serial I/O port is a DTE device. PCs
usually take the ‘terminal’ role in communications. Modems should always be DCE
devices. To connect an SLTA-10 Adapter to a PC, simply connect one end of the
serial cable to the SLTA-10 Adapter, and the other end of the cable to the PC’s serial
port. To connect an SLTA-10 Adapter to a modem, a special null modem cable must
be used. Note that most standard off-the-shelf null modem cables will not work in
this configuration.
Echelon offers the Model 73380 SLTA-10 Null Modem Cable, which is a DB-9 male to
DB-25 male null modem cable. This and other cables used with the SLTA-10 Adapter
are described in detail in the chapter.
Attaching the SLTA-10 Adapter to a PC
Most PC serial I/O ports have a g-pin male DB-9 connector, although some have a 25
pin male DB-25 connector. Most serial I/O ports are hard-wired as DTE devices.
If connecting to a PC or modem equipped with a DB-9 connector, then use a straight-
through cable with one end terminated with a DB-9 male connector and the other
end with a DB-9 female connector. Plug the male end into the SLTA-10 Adapter and
the female end into the serial I/O port.
3-2
Cabling and Connections