The Spanish Penal Procedural Law (in Spanish Ley de Enjuiciamiento Criminal, henceforth LECrim) regulates in a specific chapter the interception of the telephonic and telematic communications. This chapter is in a title dedicated to all the measures of investigation which affect to the article 18 of the Spanish Constitution (henceforth, CE). It necessarily means that the interception of the telephonic and telematic communications has consequences in some right or rights established in such art. 18 CE. What are these rights? This is the first question we will try to answer.
The article 18 CE gathers four very important rights, indeed we call them fundamental rights for the position they occupy in the CE. The first is the right to the intimacy, the second is the right to the inviolability of the domicile, the third is the right to the secret of the communications, and the fourth is the right to the data protection. Evidently, you now think that you already know what is the right affected by the interception of a telephonic o telematic communication, and I confirm to you that you are right, is the right to the secret of communications, but there is other right likewise affected and probably you have not thought in it, this is the right to the data protection. And if we think a little more we find another right indirectly affected, the right to the intimacy. Let see deeper to what I am referring. 
We identify very easy the right to the secret of the communications because this is what we are doing when we are maintaining a conversation by telephone, we are transmitting a message, we are part of a process of communication. The right to the secret of the communications guarantee that the parties who are exchanging information cannot be spied without their permission, a third party can only acquire knowledge of the message transmitted if the parties taking part in the process of communication allow it. Such right is complex, it doesn’t only guarantee the secret of the content of the communication, it also protects the identity of the parties involve in the process of communication, or the proper existence of the communication. Furthermore, there are two acts which may infringe the right to the secret of the communications, the interception of the communication as such, and to know the message without the consent of one of the parties, because when one of the parties authorizes, gives consent, other person to have access to the message transmitted there will not be an infringement of the art. 18.3 CE. We can even be more precise, what protect the right to the secret of the communications is a communication in process, when the communication has ended the message will be protected by the right to the intimacy but not by the right to the secret of communications.
The right to the data protection, is a right which protects the data that may serve to identify a person. Due to the new technologies, I am talking about the called smartphones, a phone may generate a lot of data related to a conversation, as for example the exact position of the parties talking. All these data is protected by the right to the data protection. 
The right to the intimacy will operate where the right to the secret of the communications cannot arrive, as I said before, a message which is intercepted by a third party once the process of communication has concluded, will not be protected under the right by the secret of the communications, but under the right to the intimacy.
The CE treats in a different way, these three rights. While the right to the secret of the communications needs a judicial authorization to allow a legitimate interference, the right to the intimacy and the right to the data protection don’t need it. In the latter case which will allow a legitimate interference with this rights, is a legal habilitation and the compliance with the principle of proportionality. But what I have said is a general rule, the regulation of these rights when they are in connection with of a telephonic or telematic communication has been redefined by the LECrim. Now the LECrim demands a judicial resolution in both cases, when the judicial police asks for an authorization to have access to the content of a phone call, and when the judicial police asks for an authorization to have access to the data related to such phone call. Notwithstanding there are some exceptions to this requisite, there are data which may be obtained by the judicial police without a judicial authorization, these exceptions are also regulated in the LECrim.
Summarizing, the interception of a telephone call will need a judicial authorization always, and the data associated to it in some cases, in this last case it depends to what the LECrim says.