T.E.M. A07B500S, Manual

Page: 30 / 131

A07B500S manual
Pag. 30
Pushing the blue button (REMOTE 232/485) recalls the remote control page.
The transmitter has three serial ports, one front and two rear ones. The first, COM1, allows direct
connection with a PC or a GSM cellular telephone equipped with an RS232 port.
The second one, COM2, allows connection with a power amplifier using the same port, and as such is able to
transmit data from another equipment provided with software for a remote connection over long distances.
The third one, COM3, is used for the N+1 system using a loop created with an RS485.
Using COM1, it is possible to dialogue with a connected PC directly with, or through, a GSM. For
such use, a program created through National’s LABWIEW program is supplied which can be
easily installed on a PC (PENTIUM II or higher).
To directly dialogue with a PC, install the program. Go to the remote control page by pressing the blue key
on the front panel. Choose first COM1 using the horizontal cursor, then the PC option with the vertical cursor,
finally pressing ENTER. A LED should light up indicating a remote connection with the PC, which is
connected to the transmitter using a DB9 male – DB9 female cable. Following the instructions given, start
the program on the PC. After a few seconds, the connection should become active and, using remote
keyboard, it should be possible to control the transmitter.
To dialogue with a PC directly through a GSM phone requires connecting a GSM,
enabled for data
transmission, to COM1. On the remote control page, select the GSM option, wait some second for the
connection and read the GSM FIELD value (must be >10 for correct connection ) and press ENTER when
the cursor is on the GSM labele.
Wait for the PC to indicate that it has also connected to the
telephone line via an analogue modem . The program installed on the PC uses all available drivers and
resources already installed. As such, it is only necessary to dial the number of the cellular phone to create a
remote connection with the transmitter.
COM2 cannot be accessed via the keyboard, but is rather activated automatically if an amplifier is connected
to it. If an amplifier is connected, the word OFF next to COM2 on the remote page will be substituted by the
same of the connected amplifier.
Data from the serial connection is transmitted solely using the two RX and TX port cables as a
communication protocol has been created (AES-EBU SP490), similar to that used for data
transmission on the RDS system used in the broadcasting field. This protocol allows for a huge
reduction in error rate, which is especially important when changes to the transmitter’s parameters
are made remotely. A system of data transmission similar to that of the RDS was chosen because,
as the size of data from that system is similar to our board, the protocol allows the operation even
with very low signal-to-noise ratio, and particularly because this avoids creating yet another
untested personal protocol.