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Multi-Frequency (MF) R1/R2 Software for Multi-Frequency Signal Receiving


Toronto, Canada – GAO Research Inc. ( is offering its multi-frequency (MF) R1/R2 software with highly optimized assembly or C implementation. It is fully compliant with the ITU-T Recommendations Q.320, Q.322, Q.323, and Q.441 for multi-frequency signal receiving equipment.

This MF R1/R2 software features low data and program memory requirements. Signalling systems R1 and R2 are used for inter-register signalling. The R1 signalling system is specified by the ITU-T as the North American standard and the R2 signalling system the specification used in Europe.

Both R1 and R2 signalling systems consist of two parts: line signalling and register signalling. Line signalling is used to handle line and supervisory signals. Register signalling is used for address signals. R1 Register signalling handles address signals using MF in-band pulse signalling at frequencies of 700 to 1700 Hz at 200 Hz increments. The combination of two of these frequencies determines the signal. R2 Register signalling handles address signals also by sending a combination of two fundamental frequencies. The R2 system uses two different sets of six frequencies to combine for the forward and backward signals.

This MF R1/R2 software belongs to GAO’s family of Telephony Software. Other products in this line include Dual Tone Multi-Frequency (DTMF) Software which is widely used in interactive control applications such as telephone banking, electronic mail systems, and many other menu-driven operations that respond to digits entered from a telephone. This line also includes Acoustic Echo Cancellation Software (AEC) , Voice Activity Detector (VAD), Comfort Noise Generator (CNG) and Automatic Gain Control (AGC) Software. GAO provides a complete package for telephony that includes speech compression modules and telephony modules. The software packages can be used for feature phones, Internet phones, multi-channel computer telephony boards, soft PBXs and Voice over IP.

Source: GAO