URI allows a standard land or mobile FM radio to be connected to a host computer via a USB interface. Potential radios include amateur, business, public service/safety, GMRS, citizens band, etc. The host computer requires appropriate software, such as app_rpt with chan_usbradio, to drive the device. These applications currently run under Asterisk/Linux. URI may be used for remote radio control or can link two or more radios in repeater mode. Audio can be passed through VOIP/Ethernet. Many radios provide an interface connector for external access. These signals can be easily connected to the URI’s standard DB25 connector. The URI contains the C-Media CM119B, a high-quality full-duplex USB audio controller. One channel of receive audio and two channels of transmit audio are provided. Radios that have separate voice and CTCSS signals are supported. The second audio channel may be used as a line monitor. URI has dedicated input pins for CTCSS and COR and an output pin for PTT. There are also 8 general purpose I/O pins that may be controlled by software. Each audio output channel is fed through a 3-pole low-pass filter with a 4KHz cutoff frequency. The filter outputs are AC coupled through 10µF bi-polar capacitors. This allows low-frequency CTCSS signals to be passed un-attenuated when driving a low-impedance device. The filter outputs may be DC coupled if desired by installing internal jumpers. Features Easy radio connections High-quality audio CM119B audio controller Low cost PTT, COR, CTCSS signals 8 GPIO +6dB gain op-amp Full RF filtering Internal EEPROM for storing tuning parameters on the device Includes a 3ft. USB-A to USB-B cable (color may vary from photo)
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