| Year | 1907 |
| Date | 07-Nov |
| Volume | 17 |
| Issue | 341 |
| Page | 434 |
| Category | Electrical |
| Part | |
| Title | How to Make an Inter-Communication Telephone |
| Author | Fred Rudolph |
| Notes | Desk instrument, diagram of connections for five-station inter-communication installation with lever selector, simplified speaking circuit between two stations, |