User's Manual

Point to Multi-point Operation

In this mode, a Master module will broadcast or transmit data to all available Slave

modules operating on the same frequency. All Slaves will receive data from the Master

and the host software will determine which of the Slaves transmit data back to the

Master. It is invalid for more than one Slave to respond at the same time. The Master will

only receive data that is transmitted by the Slave. Slave-to-Slave operation is not

possible. It is however possible to have several Masters which allows communication

from 2 or more Masters to broadcast to all available Slaves. Only one Master should

transmit data at a time. All data is transmitted in packets with CRC checksums. If the

received data is corrupted, the module will disregard it and not forward it to the host. The

host is responsible for the data link integrity.

To set up for Point To Multi-point operation enter AT\I1 command followed by the

carriage return character (<CR> or the Enter key), to both the Master and Slave modules.

Issue ATS0=2<CR> to the Master or broadcasting module(s). The module will respond

by sending “OK” result code. The Master module will wait 5 seconds then display the

appropriate CONNECT result code followed by “MASTER @ 9.15.02M”. Set-up all

Slave Modules by entering the ATS0=1<CR>. The Slave modules will respond with the

“ OK” result code. The Slave modules will wait 5 seconds then display the appropriate

CONNECT result code followed by “ SLAVE @ 9.15.02M”. The modules are now ready

for operation.

Setting and storing the modules settings into the modules Non Volatile Memory

(NVRAM) with the AT&W command will allow the modules to retain their DTE speed

and command settings in the event of a power loss.

Notes: Care should be taken when implementing this method. Some commands or

features may work differently in this mode.

1) The CONNECT and the MI signal indicates that the module is in broadcast mode, not

that the module is in data mode.

2) The –An, Bn, Mn, %Sn, \Tn, %Un, commands and S7, S18 registers are invalid if \I1

is set.

3) Frequency Hopping is not available in this mode.