JPH01159443U - - Google Patents

Info

Publication number

JPH01159443U

JPH01159443U JP5439288U JP5439288U JPH01159443U JP H01159443 U JPH01159443 U JP H01159443U JP 5439288 U JP5439288 U JP 5439288U JP 5439288 U JP5439288 U JP 5439288U JP H01159443 U JPH01159443 U JP H01159443U

Authority

JP

Japan

Prior art keywords

telephone line

telephone

line network

predetermined period

signal

Prior art date

1988-04-22

Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)

Pending

Links

• Espacenet
• Global Dossier
• Discuss

• 238000010586 diagram Methods 0.000 description 3
• 238000001514 detection method Methods 0.000 description 1