NL54342C - - Google Patents
Info
- Publication number
- NL54342C NL54342C NL99505A NL99505A NL54342C NL 54342 C NL54342 C NL 54342C NL 99505 A NL99505 A NL 99505A NL 99505 A NL99505 A NL 99505A NL 54342 C NL54342 C NL 54342C
- Authority
- NL
- Netherlands
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M17/00—Prepayment of wireline communication systems, wireless communication systems or telephone systems
- H04M17/02—Coin-freed or check-freed systems, e.g. mobile- or card-operated phones, public telephones or booths
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M1/00—Substation equipment, e.g. for use by subscribers
- H04M1/66—Substation equipment, e.g. for use by subscribers with means for preventing unauthorised or fraudulent calling
- H04M1/677—Preventing the dialling or sending of predetermined telephone numbers or selected types of telephone numbers, e.g. long distance numbers
Landscapes
- Engineering & Computer Science (AREA)
- Computer Security & Cryptography (AREA)
- Signal Processing (AREA)
- Computer Networks & Wireless Communication (AREA)
- Monitoring And Testing Of Exchanges (AREA)
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DET53058D DE719605C (en) | 1939-11-12 | 1939-11-12 | Zone determiners in telephone systems, especially for charge control in coin telephones with network group traffic |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| NL54342C true NL54342C (en) | 1943-04-15 |
Family
ID=5832087
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| NL99505A NL54342C (en) | 1939-11-12 | 1940-11-11 |
Country Status (5)
| Country | Link |
|---|---|
| BE (1) | BE439701A (en) |
| CH (1) | CH219811A (en) |
| DE (1) | DE719605C (en) |
| FR (1) | FR868947A (en) |
| NL (1) | NL54342C (en) |
-
1939
- 1939-11-12 DE DET53058D patent/DE719605C/en not_active Expired
-
1940
- 1940-11-07 BE BE439701D patent/BE439701A/xx unknown
- 1940-11-11 NL NL99505A patent/NL54342C/xx active
- 1940-12-13 CH CH219811D patent/CH219811A/en unknown
- 1940-12-31 FR FR868947D patent/FR868947A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE719605C (en) | 1942-04-23 |
| BE439701A (en) | 1940-12-31 |
| CH219811A (en) | 1942-02-28 |
| FR868947A (en) | 1942-01-20 |