The Federal Communications Commission (FCC) has mandated all public safety and industrial/business licensees to convert existing 25 kHz radio systems to a minimum narrowband of 12.5 kHz efficiency technology which was effective January 1, 2013.
What is the purpose of the mandate?
VHF and UHF frequency bands are very congested today, which makes it difficult for licensees to expand or convert existing systems. The mandates purpose is to increase the efficiency and allow the creation of additional channels within the same spectrum for either increased voice paths on existing channels, or better operating efficiency on narrower channel bandwidths. The FCC rule requires 12.5 kHz or equivalent efficiency.
Any of the following meet the 12.5 kHz equivalent efficiency requirement:
One voice path in a 12.5 kHz channel
Two voice paths in a 25 kHz channel
Data rates of 4.8 kbps per 6.25 kHz channel, such as 9.6 kbps per 12.5 kHz and 19.2 kbps per 25 kHz channel