| Year | 1907 |
| Date | 31-Oct |
| Volume | 17 |
| Issue | 340 |
| Page | 412 |
| Category | Electrical |
| Part | |
| Title | How to Make an Inter-Communication Telephone |
| Author | Fred Rudolph |
| Notes | Diagram of connections of a five-station intercommunication telephone system with lever selector, simplified diagrams of speaking circuit & ringing circuit |