ERICSSON ARD561

 Introduced around 1970 the Thorn Ericsson ARD561 had an extension capacity of 270, with a three digit numbering scheme.  The system was crossbar.

Capacity - Fully equipped
Extensions - 270
Exchange Lines - 40
Connecting Circuits - 20
Operator Positions - 3
Registers - 6
Enquiry Circuits - 6

Pictures
Taken at a National Bus Company site in 1970

Last revised: May 03, 2019