| Year | 1907 |
| Date | 24-Oct |
| Volume | 17 |
| Issue | 339 |
| Page | 408 |
| Category | Answers to Correspondents |
| Part | |
| Title | See handbook "Telephones and Microphones", "Practical Telephoning" by Jas. Bell and S.Wilson, "The Practical Telephone Handbook" by Joseph Poole |
| Author | T.D.G. |
| Notes |