KEY-UNIT No. 4
Used with a Sender No. 9A, 9B and 9B-1 on public exchange switchboards and PMBX No. 1A / PMBX No. 11 switchboards.

Use
Key-Unit No. 4/1A - Used in public exchange switchboards and PMBX No. 1A & 11 switchboards.
Key-Unit No. 4/2A - Used in public exchanges on DQ operator switchboard positions.
Key-Unit No. 4/3A - Used in public exchanges on International operator switchboard positions.

 

Key-Unit No. 4/1A

 
 
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Last revised: February 24, 2021

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