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Introduction to RSS
and Radio Programming
By Robert W. Meister WA1MIK

Motorola Cdm Programming Software
Programming Motorola Radio Cdm750

This article assumes that you have read the other background articles listed on the index page.

Most Motorola radios built since the mid to late 1980s (base stations, repeaters, mobiles, portables, and even pagers) are synthesized and programmable. This means they don't use individual crystals to determine the transmit and receive frequencies. Also, these and other parameters can be altered without complex and difficult internal component changes. The Personal Computer (PC) has become the instrument of choice for programming radio parameters.

Motorola sells the programming software for all of its two way radios via Motorola's purchasing website. You'll visit the site, create an account (specify you're an End User), and then search for the part number for the software you need. Motorola will sell you the software online via credit card. Download Motorola CPS Software and Cable Ordering Guide Download the TDFM-9000 Code-Plug Info PDF, – This describes what codeplugs are used on what modules as listed above. Download codeplugs for APX 7000 (T30xx) and 8000 (T4000) RF modules. CDM1250 User Guide 1.3 MB PDF CDM1250 Specification Sheet 60 kB PDF CDM1550 User Guide 1.3 MB PDF CDM1550 Specification Sheet 90 kB PDF HMN3000B Desk Mike for control stations 3 MB PDF Of course this has been discontinued but was replaced by the RMN5068A. CDM750, CDM1250, CDM1550 Parts Lists and Accessories 381 kB PDF.

Motorola Cdm Programming Software

Radios are programmed with either Radio Service Software (RSS) or Customer Programming Software (CPS) and an appropriate interface between the radio and computer. This article will not initially cover the CPS product because I have never owned or tried to program a radio that used it.

Other manufacturers have their own proprietary software and programming interfaces. This article is limited to Motorola products.

NOTE: Trunking radios, systems, and programming information is purposely NOT covered in this article. These systems, frequencies, and operating parameters are often private or business-related and are not currently used in the amateur radio bands. RSS limits access to many trunking-related fields to authorized personnel (service shops and system administrators) by using coded System Key files.

Changeable Parameters:

Programming Motorola Radio Cdm750

Just what kinds of things can be programmed into these radios? Certainly many items are common to all radios: transmit and receive frequencies (there could be several depending on the radio), coded squelch (PL or DPL) for the receiver as well as a similar scheme for the transmitter, transmit time-out limits, squelch settings, minimum volume level, trunking parameters, signaling methods (MDC-1200, DTMF), etc. Some of these parameters are often grouped together and shared among several different operator-selectable channels; Motorola calls these 'modes' and on some radios, one mode can be shared among several channels. For the most part, modes and channels are synonymous and the names are often used interchangeably. On occasion, a few of these parameters can also be selected separately via the radio's control panel: Multiple PL (MPL), scanning, zones (groups of modes or channels), etc. Some parameters are limited to servicing the radio: output power, deviation, frequency, current limiting, etc. Motorola refers to all of this information, that's unique to each radio, as a 'code plug'. This term comes from an earlier period when certain parameters were actually selected by inserting a factory-coded plug into a socket in the radio. The name stuck, even though a lot more information is now included in the code plug. By the way, some literature will spell this as one word: 'codeplug'.

In the United States, the Federal Communications Commission (FCC) is given the task of regulating radio signals (there's probably something similar in your country). One of their rules and regulations states that the transmitting frequency of a commercial land-mobile radio may not be changeable by the user through a front panel control. USC-47-CFR-90.203(e) is quoted below:

(e) Except as provided in paragraph (g) of this section, transmitters designed to operate above 25 MHz shall not be certificated for use under this part if the operator can program and transmit on frequencies, other than those programmed by the manufacturer, service or maintenance personnel, using the equipment's external operation controls.

This means a two-way radio must be limited in such a way that the operator can only select pre-determined frequencies, such as crystal-controlled channels or some means of external programming. Most amateur two-way radios ARE frequency-agile and have knobs and controls that let the operator choose any transmit and receive frequency the radio is capable of, rather than the more restrictive method in use by commercial radios.

Radio Programming Components:

So what's actually needed to program one of these radios? Obviously you need a radio. You also need a computer (IBM-compatible desktop with keyboard and monitor, or a laptop). You need programming software installed or loaded on that computer. Last but not least, you need to connect the radio and computer together.

One or more signals are used by the radio for programming purposes. The information is transferred with one or more serial data lines. This connection is often implemented through specific pins in a microphone or accessory jack on the radio. There's no standard connection; it varies by series.

Motorola radios don't all use the same programming signals. To deal with this, Motorola designed a Radio Interface Box (RIB) with the ability to convert the variety of radio programming signals into serial port signals that PCs could use. (The model number they assigned to this unit - RLN4008 - has gone through several revisions; the latest is RLN4008E.) This is a 9V battery-powered device that converts various radio signal levels into RS-232 serial port levels. An external, 9-12V power supply may also be used to power the RIB.

Unique programming cables have a connector on one end that fits the radio, and a DB25F connector at the other end that plugs into the RIB. The programming signals and some jumpers are wired to specific pins at the RIB end. One more cable connects the RIB (with a DA-15 connector) to the serial port on your computer. Older PCs had one or more real serial ports labeled COM1 and COM2. They could be either 9-pin (newer) or 25-pin (older) male connectors on the back of your computer. Motorola sold two RIB-to-computer cables to deal with this situation. Many after-market (non-Motorola) RIBs use different connectors on the RIB-to-computer cable or provide a standard 9-pin to 9-pin cable.

The RIB and its cables, or a functionally equivalent, purpose-built, circuit is a necessary component of the Motorola radio programming environment.

Some kind of interface between the radio and the PC is necessary. Since not all users want to spend the money or require a RIB with its ability to interface to ALL Motorola radios, there are now so-called RIBless cables. These are built to provide the same functionality as the RIB and its two cables, but they do it all in one purpose-built cable that plugs into both the radio and the PC. The electronic parts are usually contained in the DE-9 connector shell. The designs vary, and some cables don't work with all computers. These are initially less expensive than a real RIB and one set of cables. Not every radio model has an equivalent RIBless cable made for it; MaxTrac and GTX radios do; Spectra radios don't. Sooner or later, you may obtain or need to program a radio that requires a different RIB-to-radio cable, and your RIBless cable will be useless. Of course, hindsight is 20-20; if you think you'll ever have more than one type of radio to program, invest in a RIB right from the beginning and make or buy radio-specific cables as needed.

Some newer desktop computers and most laptops have eliminated their serial and parallel ports. There are adapters (U

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