The PABX5 is has 5 exchange lines and 20 extensions, two of the extensions are terminated on an attendant unit allowing a receptionist
or secretary to deal with two calls at the same time. Incoming calls ring a central bell and can be answered by any designated extension just by lifting their receiver. Enquiry transfer is available at all extensions.
When purchased the PABX5 only had three exchange lines, two more relay sets where found and an extra uniselector had to be found for the 5th exchange line.
Direct dialling into the PABX5 was achieved by using the inter PBX auxiliary circuits, this allows direct access for dialling extensions.