Motorola DLR/DTR

Motorola Solutions produces a series of license-free handheld radios which operate similar to the Nextel phones using the Direct Talk mode. They are incompatible with the Nextel phones because of a software difference. 

These radios operate in the 902-928 MHz unlicensed ISM band. The International Telecommunications Union has designated this as a license-free band in Region 2, which includes the Americas, Caribbean, and certain Eastern Pacific islands. As such, this is the only wireless category that is legal to use anywhere in the United States, on the cruise ship in international waters, or in foreign ports in the Caribbean. 

The Motorola DLR/DTR series utilizes frequency-hopping, spread-spectrum technology with a maximum output power of one watt. The range is about one mile (less in urban areas and greater in rural areas). 

They operate on one of ten channels, which are also known as hop sets or frequency hop groups. Each channel uses a specific frequency hop sequence algorithm, that uses 50 distinct frequencies within the 902-928 MHz band.

Each of the channels has 15 talkgroups per channel, which operate similar to PL codes on other services. Therefore, a business operating on Channel 3 could have separate talkgroups established for different departments (supervisors, maintenance, housekeeping, operations, customer service, and so on). Only a one talkgroup can have a conversation on a single channel at a time. 

In addition to voice communication, the DTR series supports text messaging through a selection of “canned” or pre-defined messages. The only model which allows users to compose their own text messages is the Motorola T800, which is an FRS transceiver.

The difference between the two series is the DLR is a simpler radio without a display, with either two or si channels available, whereas the DTR offers ten channels with a display, and offers more features. Both are programmable with software available to the user.