Return to SSP (thing)

Acronym for Service Switching Point. This is what a [telecom]unications [switch] is called in an [SS7] [network]. All [phone] lines are attached to an [SSP], which is also attached to the rest of the [SS7] [network] via links to [STP]s. The [SSP] is the basic [element] of an [SS7] [network], without it the rest is useless, an [SSP] is the origination point for all [phone call]s and the activities that go with them. ([CNAM], [CLASS], [E800], etc.) In contrast two [SSP]s could be linked to allow [traffic] between them, thus removing the need for [STP]s. Note however, that this would be horribly inefficient.
Per request:
Mirror the diagram along the vertical axis to get a VERY simple picture of how this works
°/\° == Telephone
                      ______      ______
°/\° ----------------|      |    |      |
                     |      |    |      |
°/\° ----------------|  [SSP] |----| [STP]  |----
                     |      |    |      |
°/\° ----------------|      |    |      |
                     |______|    |______|