User's Manual

22 TransNET OEM Integration Guide 05-3946A01, Rev. C
SAF Configuration Example
The following is an outline for the configuration of a simple
store-and-forward link.
1. Mode X and M Radios—Can have direct reports (Mode R radios) out-
side of the chain.
2. Data (Payload)—Travels from Master to Remote, and back from
Remote to Master.
3. Mode X and R Radios—Extension links can be protected by mapping
one or more fall-back paths in case of a failure. Add secondary exten-
sion addresses (XADDR) into the
XMAP table. (See “XMAP
[00000000-FFFFFFFF]” on Page 55.) 

For example, as shown in Figure 14, Remote “D” could use Remote “C”
as its extension primary, and Remote “B” (X ADDR = 1) as an alterna-
tive in case of a failure of Remote “C” (X ADDR = 2). This arrange-
ment assumes a serviceable path between Remotes “D” and “B” and
requires Remote “D” to be programmed with XMAP = 2 to correspond
with the XADDR address of Remote “B.”
Invisible place holder
Figure 14. SAF Configuration Example
This configuration is easily arranged through the use of the Extension Map
in the MDS TransNET Configuration Software’s “Store-and-Forward
Settings.”
6.4 Using AT Commands
A TransNET network may be configured to support protocols employing
Hayes-Compatible modem commands through the radio’s AT Mode. In this
mode, TransNET units can provide a communications replacement for
dial-up modems where the RTUs and the protocol do not contain address-
ability, and the establishment of a direct-communications link is the only way
to determine if the RTU has data ready to be sent.
This requirement is common in many older SCADA systems which were
developed for direct connections where wire lines were the only communica-
tions link available at the time. Most of these older system implemented
support for the AT commands needed in the host software, so TransNET units
can be used without software modifications.
A B C D E
MODE = M
ADDR = 1234
X ADDR = Ø
X PRI = None
MODE = X
ADDR = 1234
X ADDR = 1
X PRI = Ø
MODE = X
ADDR = 1234
X ADDR = 2
X PRI = 1
MODE = X
ADDR = 1234
X ADDR = 3
X PRI = 2
XMAP = 2
MODE = R
ADDR = 1234
X ADDR = 4
X PRI = 3
TransNET
Radios:
Radio
Confguration: