Xetawave Xeta9-E, Руководство пользователя

Страница: 50 / 68

47
Specifically, the 16QAM mode at 3,535kbps should only be used for short distance,
strong signal links.
The MAS Receive Modes are based upon the bandwidth of the permitted license.
Either 12.5kHz or 25.0kHz bandwidth modulations are supported.
3.4.2 RF Protocol
The “ Network Type ” defines how this radio operates with other radios in the
network; the common options are ‘Point to Point’ and ‘Point to Multi-Point’. For
all cases, the radio will be either a Master radio (initiating contact with other
radios), a Remote/Slave (waiting for a Master radio to start communicating), or a
Repeater (waiting for a Master, and then repeating the message to another
remote/slave).
If the Network is a point-to-point network, then the transmit rate is the same as
the receive rate and will adjust based on signal quality. However, if the network
is point-to-multi-point, then the master radio can use a different modulation for
transmission than the remote slave radios; thus the master and the slave radios
may use different modulation methods. The advantage of this is to allow radios
that have a good RF connection to maintain a high-speed link to the master
while radios on the same network that have a poor RF connection can still
maintain a link at a slower data rate without penalizing the “good link” radios.
The one limiting factor is that all remote radios must be able to receive the
master, thus the master must transmit at a rate that allows all remote radios to
receive, this is typically a slower rate than many of the remotes could operate at.
Thus the “Master Transmit Rate” must be set for a multi-point network. Note
that all radios on the network must have the same settings, thus remote radios
must have the Master Transmit Rate set and the Master Radio must have all of
the receive rates set that correspond to the remote radios
Point to Point (P-P)
A point to point network consists of two radios, a master and a remote/slave. The
operating mode of the radio is set by the “
Mode ” menu which offers “ Master ”,
“ Repeater ”, or “ Slave ”. The master sends a beacon message to the remote and the
remote unit responds. Data may be transferred in either direction but the master will
tend to broadcast more often than the remote. The remote radio will link to the master
Address and the Master radio must be programmed with the slave radio’s address in
the “ Downstream Device ID ”. Likewise, the remote radio must be programmed with