As No. 310A/A, but without bell set. Suitable for use as extension telephone.
As No. 309A/A, but with Dial Dummy No. 5 fitted in place of dial.
The Telephone No. 309 was also supplied complete with a
Bell Magneto No. 24 and this combination was called
the Telephone No. 304.
From the SIEMENS BROTHERS & CO. LIMITED catalogue No.500/54
March 09, 2023