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System Overview
Interface Type (I/F Type)
An interface type must be specified for every data channel. The interface type determines the con-
trol signal arrangement used at the Node M and Node S ends of the channel. The flexibility of the
MEGAMUX PLUS system allows support of many communications arrangements, and provides
display and control over the interfaces through the supervisory port CRT. A specific interface
type is selected as a channel parameter; the control signals sent and received at the Node M and
Node S channel interfaces is then displayed as part of the channel configuration display. Custom
interfaces may also be developed; these interfaces require customizing of the data channel mod-
ule and special interface type programming.
Voice Channel Interface
A CVSD or ASP voice channel interface type is very simple. E and M signaling is supported; M
is an input control signal (input to the voice channel) and E is an output control signal.
The signal state of an M lead at one channel interface is multi-plexed through the system and
transmitted at the opposite end interface as an E lead output. The interface type is identified as I/
F type VC l; because this interface is the only one available, no parameter selection need be made
for a voice channel. The display below is the VC1 configuration interface display.
SEND : M
RCV: E
Switches and jumpers on all voice channel modules select one of the five E and M signaling types.
Each type is a different representation of the E and M On and Off states using voltage levels or
open and closed circuits. Since any of these types result in On or Off states for the signals, they
are not differentiated by the supervisory port display.
You may display and change the states of the E and M signals using Control State routines pro-
vided as part of the Diagnostics routines for CVSD and ASP voice channels. This feature allows
you to disable a voice channel when required. However, if you save changes made to the voice
channel controls, the control states are changed in the channel configuration also. Be sure to note
such changes if you make them; a voice channel thus disabled remains disabled until action is
taken through Configuration or Diagnostics routines to restore them.
PCM or ADPCM voice channels have a fixed interface type.
NOTE
Take care when forcing control signals On or Off in the Control
State Test routine. If a new configuration is activated, and the
interface type configured for that channel is the same as in the
previous configuration, the system does not attempt to change
control signal states. As a result, any signals left forced On or Off
may remain in that condition regardless of the interface type
configured for the current channel.
NODE M
I/F CONTROL [NAMES]
M
E
NODE S
036R660-000, Issue 10
2-19
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