Siemens 600Series - Manual (Page 18)

1-4 ROLMphone 300/600 Series User Guide
Options
The ROLMphone 600 series telephones are modular and support
options for data communications, a headset/recorder connection, or
additional keys. The Data Communications Option (DCO), Headset/
Recorder Option (HRO), Electret Headset Option (EHO), Analog
Adapter Option (AAO), and CTI/Headset Combo fit into recessed
module bays on the bottom of the telephone. The Keyboard Expansion
Option (KEO) plugs into a connector provided in one of the bays. The
DCO, EHO, HRO, AAO, and CTI/Headset Combo may be installed in
either module bay. Once the KEO is installed, any of the other options
may be installed in the module bay that has the KEO connector.
Figure 1-4. Option Module Bays and KEO Connector
DCO/HRO/EHO/AAO/
CTI/Headset Combo Module Bays
KEO
Connector