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How cell phone company interconnection works?
How do telephone companies interconnect with each other?
For example, user of company X calls user of company Y. Does company X have to pay company Y? Or the other way around?
For example, user of company X sends a SMS text message to user of company Y. Does company X have to pay company Y? Or the other way around?
- 1 decade agoFavorite Answer
Cell phone companies have entities called "HLR"s (Home Location Registers) and "VLR"s (Visitor Location Registers)
HLRs are like static databases. Your HLR is probably near the area where you bought the phone. They don't change much unless people add/remove/change their phone service. These keep track of what your home market is and what features you pay for on your phone service.
VLRs are different- they are dynamic- they are databases that keep track of who is nearby with their phone on.
When you turn your phone on, the nearby VLR senses your presence (through the nearby mobile antenna tower) It then hunts for your HLR to determine what features you have on your phone. If you are on some other company's network, the VLR can still find your HLR- that is, if the mobile technology is similar between the two companies. (I think this was more common in the analog mobile phone era though) The VLR will then permit you/deny you to make calls.
I don't know much about pricing; I do know that one company will have to pay the other if they have roaming agreements. Meaning, we at company A will pay you $X to allow our customers to roam on your (company B's) network free of charge.