/** Raised when a telephony provider fails, or none is registered for an operation. */
export declare class TelephonyProviderError extends Error {
    /** The provider. */
    readonly provider?: string | undefined;
    /** The underlying error. */
    readonly cause?: unknown | undefined;
    constructor(message: string, 
    /** The provider. */
    provider?: string | undefined, 
    /** The underlying error. */
    cause?: unknown | undefined);
}
/** Raised when a provider does not support an operation. */
export declare class TelephonyCapabilityError extends TelephonyProviderError {
    constructor(provider: string, capability: string);
}