The HLR Lookup, or HLR consultation, notably helps in maintaining a clean and updated database, thereby sending SMS to active phone numbers. It also helps counter the growing trend of mobile number portability, which despite its benefits to users, makes tasks more challenging for companies using this communication channel. How does the HLR Lookup work? What are its benefits and does it go as far as allowing users’ geolocation? These are the questions we propose to answer in this article.
What is an HLR?
The HLR (acronym for Home Location Register) refers to the central database of a mobile telephone network. It contains all the SIM card details of subscribers using the network in question (phone number, location of the number, etc.). Every operator has an HLR. This allows them to know if people are authorized to use the central GSM network and to keep track of how calls and messages are sent.
HLR Information
The User
- IMSI (International Mobile Subscriber Identity) – User’s unique number (stored in the SIM card)
- IMEI (International Mobile Equipment Identity) – Unique number of the mobile phone terminal
- MSISDN (Mobile Subscriber International ISDN Number) – User’s international dialing number
User’s Location
- MSRN (Mobile Station Roaming Number) – User’s address on a foreign network
- Addresses of the MSC and VLR – Approximate position of the user
What is the HLR Lookup?
The HLR consultation (HLR Lookup) involves accessing a mobile network subscriber’s information in real-time. For businesses practicing SMS marketing, for example, this notably allows them to check whether the contacts on their mailing list are up-to-date. Thus, determining the status of the concerned phone number (active, absent, blocked, suspended) and the operator it is attached to. A major advantage for maintaining a clean contact list, free from duplicates and unassigned numbers.
Other information can be obtained in real-time by conducting an HLR consultation:
- Phone number type
- Contact location (phone number and country registered for the same number)
- Country and network involved if the user is roaming
- Issues that may prevent the sending of an SMS (phone turned off, out of network, etc.)
- Number transfer from one network to another (if applicable), and the date when the phone number was last transferred
Be aware that the HLR information relates to the phone number and not the characteristics of its user.
Major Benefits
For SMS marketing operations, the HLR Lookup notably allows cleaning mobile phone number contact lists, thereby reducing costs and saving time by avoiding sending messages to invalid or deactivated contacts. This factor will also positively impact the deliverability of your shipments.
The HLR consultation also helps to achieve better targeting of different contacts and facilitates the resolution of message delivery issues.
Lastly, the HLR Lookup is useful for validating phone numbers provided in online forms.
Does HLR Lookup Allow for Geolocating Mobile Numbers?
Yes and no. As explained earlier, the HLR consultation allows for locating a contact, but in a limited way (country), referring to the place of issue of the number and not the exact location of the device. Precise geolocation would be illegal under the Law on the Protection of User Privacy.
