Black Box Black Box network services, PSD-4 manual Technical Guide, Control Signals, Block Diagrams

CHAPTER 5: Technical Guide

5. Technical Guide

5.1 Control Signals

MAIN CHANNEL CONTROL SIGNALS

RTS (DCD)

•In RTS/DCD contention mode: follows RTS (DCD) of the selected sub-channels.

•In Data Contention mode: ON if one of the sub-channels RTS (DCD) is ON.

CTS

On only when the CTS signals of all active sub-channels are ON. A sub-channel is active if it is connected to a modem and the DSR signal is ON (enables connection of dialup modems to the PSD).

DSR (DTR)

ON if one of the sub-channel’s DTR (DSR) is ON.

SUB-CHANNEL CONTROL SIGNALS

RTS (DCD)

• Follows the main channel RTS (DCD) (unless the sub-channel is disabled).

CTS

•In RTS contention mode: selected sub-channel follows DTS signal of main channel.

•In Data Contention mode: sub-channel receives CTS from main channel immediately after it raises RTS (unless the sub-channel is disabled).

DSR (DTR)

Follows the main channel DSR (DTR).

5.2 Block Diagrams

Figures 6 through 9 illustrate the flow of data and control signals in the PSD, in different DTE/DCE configurations:

	Main	Sub-
Figure	Channel	Channel
Number	Configuration	Configuration
6	DTE	DCE
7	DTE	DTE
8	DCE	DCE
9	DCE	DTE

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