OK, you understood ‘cops’ that is not a expression we generally use here in the UK. We Brits traditionally often refer, respectfully, to our ‘boys in blue’ as ‘bobbies’ or ‘the old bill’.
Anyhow, given that, I am likely to presume that you’re asking about the United states police force and their longstanding joint venture with the Motorola Business. OK, here goes…
According to Motorola’s own website,
“Law enforcement communications and police communications are essential assets to the safety and security initiatives in any community. Advancing police communications allow law enforcement to be more mobile and more rapidly respond to issues. Motorola offers an extensive product line to enhance law enforcement communications with less paperwork and faster, highly reliable performance”.
Motorola manufactured vehicle radios as early on as the 1920’s and US police and the fire brigade used a few of these, but it really was not until 1930 that the initial police force car two way radio was developed and constructed by Motorola. In line with the official internet site,
“Sales of Motorola police radios began in November 1930. Among the first customers (all in the U.S. state of Illinois) were the Village of River Forest; Village of Bellwood Police Department; City of Evanston Police; Illinois State Highway Police; and Cook County Police in the Chicago area. As more police departments used radios, challenges emerged. Rough roads, engine noises, interference, high power consumption, and frequency instability led Paul Galvin to recognize that police departments needed a radio specifically engineered for patrol cars”.
In 1936, the Motorola Police force Cruiser Radio was released. It was a success and Motorola have been a trusted brand name by US Law enforcement since. In 1939, engineer Don Mitchell created the Mobile T6920 AM Transmitter. It was another achievement, becoming a commonsense choice for that law enforcement as,
“This complete Motorola two-way radio system was priced about one-fourth as much as the competition’s, and the transmitters could be installed in cars that already had receivers in the same frequency band. In 1940 the Police Department in Bowling Green, Kentucky, became the first customer for a complete Motorola AM two-way radio system. The radios were so well-designed that Galvin Manufacturing produced the same models for several years, until FM technology replaced them in the 1940s”.
Noticeably, the US police force use a long and abundant connection with the Motorola Company. This evidently applies to walkie-talkies also. It makes good sense to employ a trusted, easy to implement product for successive generations of officers, who often have to respond promptly and impulsively to various troubles.
The very first police to utilize two way radios were in fact Australian, but following the Second World War, mobile radios were to become standard issue in the majority first world states.