| GMD | Text |
| Classification | 621.38 Up1 |
| Publisher | London, Methuen Children's Book, c1985 |
| Subject | Telecommunication systems -- Juvenile literature.Telecommunication systems - For children. |
| Series | Turning points. |
| Description | 24 p. : ill. ; 21 cm. |
| ISBN | 9780416500301 |
| Additional ISBN | 0416500307 |