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3.3. "Point-to-Point" Mode
In this mode, two B900ss-20 Modems can communicate together without getting any
interference with other Modems.
For this purpose, their work is synchronized and constantly jumping frequency,
avoiding interference with another transmitter: if one or more channels are busy, the
data will be transmitted through another channel.
On the other hand, a "Personal Network" owns each set of modem. The data used for
a "Personal Network" cannot be intercepted by another "Personal Network". Each
"Personal Network" owns a Master, which handles the communication (synchronization,
priority, etc.) and a Slave that obeys its Master.
The first synchronization is named "Acquisition", and lets a Slave get acquainted with
its Master (No. of Personal Network, Frequency Table used, etc.). Eventually, at each
powered reset, the Slave will synchronize, then later be able to communicate with its
Master. A "Lock" signal shows if a Slave has been synchronized with its Master or not.
Eventually, this synchronization is maintained all along the Master/Slave Dialogue.
A hardware flow control (RTS/CTS) is present on the Modems serial link in order to let
the user know that the buffer (130 characters) starts to saturate. The alarm level is by
default 130 characters and can be programmed through the S215 Register.
Finally, an Ack_Tx signal, synchronized on the RTS signal, allows the transmitter user to
know if the receiver user has received a data frame or not.
For more specific information and to get the Time Series Charts, see the following
chapter ("Advanced Part") and the Appendix 5.
