Specifications

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DX-120 Installation and Maintenance Manual OVERVIEW
Configuration
The Vertical DX-120 platform is comprised of one full-featured key telephone model and two modular KSUs (Key
Service Units). Several modules are available for enhanced system applications and configuration expandability.
KSU1 COMPONENTS
The CPM (Central Processor Module) is installed inside of KSU1 and connected to the 408M ribbon cable J4 (also
labeled “To CPM”).
• The CPM contains:
- Two serial ports
- Two music ports
- One control contact (external paging/LBC/gate control)
- One external page equipment interface connection
- Socket connectors for the KSU2 (labeled “2nd Cabinet”), MDM, and VP modules (AAM, 7271C, and
7270C)
• The standard 408M (part of 7201) contains:
- 4 CO line ports
- 1 power failure transfer port for the first CO line circuit
- 8 digital ports
- a ribbon cable (J1, also labeled “COM4”) for connection to the COM4 module (PN 7210) in KSU1
- ribbon cable sockets (J2 and J3, also labeled “To DPM8”) for connection of DPM8 (PN 7220) or
DPM16 (PN 7221) module
• The standard APM4 (part of 7201) contains four analog device ports (installed on ribbon cable J5, also
labeled “APM4”)
KSU2 COMPONENTS
The standard 408E contains:
• 4 CO line ports
• 1 power failure transfer port for the first CO line circuit
• 8 digital ports
• a ribbon cable J1, also labeled “COM4”) for connection to the COM4 module (PN 7210)
• ribbon cable sockets J2 and J3, also labeled “To DPM8”) for connection of DPM8 (PN 7220) or
DPM16 (PN 7221) module
• a shielded cable (J4) for connection to CPM socket JP2 (also labeled “2
nd
Cabinet”) in KSU1
Configuration (continued on next page)