What signals shows the standard capabilities of the called side facsimile?

The standard capabilities of the called side facsimile can be indicated by several signals, including the "CNG" (Calling Tone) signal, which alerts the receiving fax machine to an incoming fax transmission. The "CFR" (Confirmation Receipt) signal confirms successful reception of the fax. Additionally, the "CNG" may be followed by the "CFR" signal, ensuring that the sending side receives acknowledgment of the transmission's success. These signals help facilitate effective communication between the sending and receiving fax machines.