Specifications

Power to operate the DAI-2 is supplied by a 12 volt DC wall-plug transformer that is included with the DAI-2. This
transformer is designed for 120 volts AC at 50-60 Hz and is rated at 500 milliamps. The leads of this transformer
should be stripped and tinned and connected to the appropriate screw terminal connectors on the relay panel. The
positive lead (usually denoted by a white stripe) connects to the +12V terminal and the negative lead connects to
GND on the relay panel. (See figure 3.2) Power supply polarity should be verified before the connections are made to
avoid damage to the DAI-2.
3.3 Telephone Interface
The RFC-1 is designed to be connected to an ordinary (POTS) telephone line. In some cases a telephone line is
either not available or is prohibitively expensive. There are several alternatives to a regular telephone line that are
compatible with the RFC-1.
3.3.1 Cellular Telephone with an RJ-11 Adapter
It is possible to connect a cellular telephone to the DAI-2 in place of a telephone line. Some cell phone manufacturers
offer devices that provide a cellular telephone with a standard RJ-11 jack. These devices emulate a standard
telephone line including dial tone, ring voltage and battery. Additionally, the cell phone will usually need to be
outfitted with an external antenna and a constant power supply. Several manufacturers offer these items as part of
their product line but product lines change rapidly. The best approach is to discuss your needs with your supplier to
find a solution that will work.
Most of these RJ-11 adapters generate a square-wave ring signal on an incoming call instead of the sine-wave ring
voltage that is found on a normal telephone line. The DAI-2 has a firmware adjustment that will enable it to recognize
the non-standard ring signal. The Programming section of the DAI-2 documentation provides details on making this
adjustment.
3.3.2 Fixed Location Cellular Telephones
An alternative to using a mobile cell phone with an RJ-11 adapter is to use a cell phone designed specifically for fixed
locations. These phones usually include an RJ-11 connector for outboard equipment and provide a cleaner solution
than the adapter approach. They also tend to be more expensive but they include some items that are extra in the
mobile cell phone approach. Telular, Inc. is a manufacturer of fixed location cell phones. They can be reached at
[phone] or http://www.telular.com.
3.3.3 Rural Radiotelephones or Ranch Telephones
Rural radiotelephone systems, or "ranch phones”, are systems that use a full duplex VHF or UHF radio circuit to
extend a telephone line. Two small transceivers are used in this system. One end is connected to a regular
telephone line, the other end has an RJ-11 jack that emulates a regular telephone line. Rural telephones have a
range of roughly 1 to 10 miles depending on terrain. The transmitter power levels are usually in the range of 1 to 10
watts. Because they contain transmitters, rural telephones must be licensed. Channels are scarce in the more
populated areas of the country but are usually available in the areas where rural telephones are most often needed.
Rural radiotelephones usually cost several thousand dollars for a typical system but there is no recurring cost for
service once installed. DX Radio Systems is a provider of radiotelephones. They can be reached at [phone]
or http://www.tpl-dxrs.com.
DAI-2 Installation page 3. 5