Specifications

ELAN AUDIO - SENTINEL / RCU-01 RCU01R02 PAGE 20/49
7.7 Hardware Configuration
• Direct Connection This is for a 'simple' point to point hardwired serial connection. There is no other hardware
involved apart from a NULL modem cable.
• Radio Connection This utilises a simplex radio modem link as the communication medium between SENTINEL
and the RCU. Currently the TRIO TC-xxxSR series of radio modems are supported. They are available on a
number of frequency bands and provide a 1200bps simplex link. The serial cable connections are as shown in the
'Radio Modem Cable Example' in the Appendix.
• PSTN modem This requires an approved modem such as the Maestro Woomera modem configured for PSTN
dial up and uses either a PABX or PSTN dial up line connection as the communication medium between
SENTINEL and the RCU. The standard modem RS232 cable supplied by the modem manufacturer is suitable for
use at both SENTINEL and the RCU.
• Leased Line This requires an approved modem such as the Maestro Woomera modem configured for either two
wire or four wire leased or private line connection as the communication medium between SENTINEL and the
RCU. The standard modem RS232 cable supplied by the modem manufacturer is suitable for use at both
SENTINEL and the RCU.
• Mobile modem This requires an approved modem such as the Maestro Woomera modem configured for PSTN
dial up and uses either a mobile phone dial up line connection as the communication medium between SENTINEL
and the RCU. The standard modem RS232 cable supplied by the modem manufacturer is suitable for use at both
SENTINEL and the RCU.
Modem Setup and Initialisation.
To use a modem in the SENTINEL /RCU system it is essential that the following parameters / functions MUST be
available and configured on both the host and the remote modem. The configuration requirements are the same for
ALL modems.
1. The serial port data rate MUST be fixed to 9600.
2. The modem MUST hang up when DTR is dropped.
3. The modem DCD MUST track the line carrier.
4. The modem MUST be able to auto answer.
Most modems have the ability to configure 2, 3 & 4. Only some modems can configure 1.
Auto baud rate detection on the serial port is useless for an auto answer modem as the serial port data rate will track
whatever the line connection speed is unless there has been serial communications via the serial port before the line
connection. At the RCU it is impossible to ensure that the RCU communicates with the modem before a connection
might occur. Periodic communication could abort an incoming call and / or the modem could be reset / replaced
without the RCU knowing.
MAESTRO Woomera Modem Initialisation (See section 4.7 for complete procedure)
In windows 95 use ‘HyperTerm’ set up for direct access to com port. 9600,8N,1
Send the following to the modem
Command Comment
at&f Reset modem
ats0=2&c1&d2e0m1&w0 Auto answer after 2 rings, DCD tracks line carrier, No echo,
DTR hang up, Speaker on until connected, Save config
at+ms=11,,,,,, Force connection speed ( NB There are six commas )
at&w0 Save configuration
NOTE: If you get an error response from the modem, then it is not suitable to be used at the RCU end.
Some modems will reject the &b1, fixed serial port data rate, command. This can be omitted for the host modem. It is essential for
the RCU modem. The MAESTRO Woomera modem automatically supports fixed serial port data rate and therefore doesn’t require
and doesn't support the &b1 command.