"Simplex - Key Telephone System"
(The large picture changes on "mouse over" the number of the phone or the circuit diagram).

Picture
System overview: without intern. communic. 306 407
1913 Catalog number: 5701 5711 5712 5715 5718 1924 Catalog number: 5xxx
Circuit number: 158 184 187 186 183
System overview: with internal communic. 359 476
1913 Catalog number: 5721 1914 Catalog number: 5724 5750 5761
Circuit number: 382 482 377 477
1924 Catalog number: 5yyy
1925 Catalog number: 5560 5565 5570 5574 5580/81 5583 5584 5585 5586
Circuit number: AS-240 AS-240 AS-241 AS-241
1925 Catalog number: 5890 5891 5891Z 5892 5892W 5892Z 5893/94 5895 5895Z
Circuit number: AS-241 AS-241

System overview: JNS-102/2 Schema
1932 Catalog number: 7860/61 7960/61/64/65 1935 Catalog number: 7849
Circuit number: NS-306 NS-306