"It is shall be unlawful for any person, not being authorized by all the parties to any private communication or spoken word, to tap any wire or cable, or by using any other device or arrangement, to secretly overhear, intercept, or record such communication or spoken word by using a device commonly known as a dictaphone or dictagraph or walkie-talkie or tape recorder, or however otherwise described:
It shall also be unlawful for any person, be he a participant or not in the act or acts penalized in the next preceding sentence, to knowingly possess any tape record, wire record, disc record, or any other such record, or copies thereof, of any communication or spoken word secured either before or after the effective date of this Act in the manner prohibited by this law; or to replay the same for any other person or persons; or to communicate the contents thereof, either verbally or in writing, or to furnish transcriptions thereof, whether complete or partial, to any other person: Provided, That the use of such record or any copies thereof as evidence in any civil, criminal investigation or trial of offenses mentioned in section 3 hereof, shall not be covered by this prohibition."Penalty upon conviction for violation of the said section is imprisonment for not less than six months or more than six years.
This law was approved on June 19, 1965 which explains its outdated enumeration of devices used for illegal recording. With the phrase "any other device or arrangement", the law still clearly includes 21st century devices such as smartphones and digital recorders. But the enumeration of outdated devices is not the only thing outdated about this law. Some courts in the United States have already recognized that their laws on wiretapping and privacy of communication have been misused to forbid any recordings of people without their knowledge. A report says one court has declared that secretly recording a conversation, in this case an iPhone, is legal as long as no crime was committed with the recording and the recording was for a legitimate purpose. For the recording to be illegal, the intention must be to commit tort against the individual beyond the recording itself and not for any reasonable purpose. (https://www.techdirt.com/articles/20100818/17141010676.shtml) Moreover, many states in the US have already adopted the principle of "one party consent recording of oral communications" which means that secretly recording a conversation is legal as long as the one recording it is a party to the conversation.
With Republic Act 4200 still in effect, however, secretly recording a conversation can still jeopardize the person who recorded the conversation or the person who shared the recorded conversation knowing that it was secretly recorded.
Be careful of this outdated law.