The DRP enables a remote terminal connected to an external modem to communicate with the CPU as either the
system console or as a terminal on an intelligent asynchronous controller (IAC) port. There are four ports going
into the DRP: a modem (to the remote service center), a system console interface (to the system console
terminal), a CPU port interface (to the CPU - PIO/DCH chips), and an IAC interface (to an IAC line). Security
for the customer system is provided in the three access levels, a system password, and the dialback feature. An
extensive power-up DRP self-test is provided, and any failures are reported via the front panel LED, or to the
system console
Several different DRP modes allow a remote terminal connected to the DRP to function in different capacities.
The major modes are: normal, system, user, and conversation. Most of these major modes are further defined
by submodes. A brief explanation of each mode and its submodes follows.
3.3.5.1 Normal Mode - An ECLIPSE MV/7800 system is configured to normal mode after system reset, or after
all power-up self-tests pass. If Automatic Program Load has been selected, the master console will communicate
with the CPU port via a firmware connection. Otherwise, the master console comes up connected to the 8031
processor running SCP-CLI. Normal mode is further subdivided into local system mode or local SCP mode.
3.3.5.2 Local System Mode - In this mode, the CPU is normally running the operating system and PIO/DCH
controller is directly connected to the system console. The IAC port is also directly connected to the user
terminal.
Pressing the BREAK key at the system console forces an NMI to microcode, which sends the interrupt to the 8031
monitor. The SCP echoes the prompt SCP-CLI>, allowing COMSWITCH-II or SCP commands to be accepted
based on the current access level. See Figure 3-13 for the DRP configuration for this mode.
3.3.5.3 Local SCP Mode - In this mode, the CPU is running the operation system or is halted via the SCP
command HALT. CPU system console output is held off by holding the PIO/DCH controller's clear to send
(CTS) line busy. If the CPU is running the operating system, the IAC and user console connection are available.
The SCP-CLI> prompt appears at the system console waiting for either SCP or COMSWITCH-II command input.
See Figure 3-12 for the DRP configuration for this mode.
3.5.5.4 System Mode (Remote) - System mode refers to the remote modem terminal connected as if it were the
system console. Full access must be granted before this mode is entered. Remotely, this allows a modem terminal
to be running as the system console under the operating system, or running the system control program. System
mode is further subdivided into remote system mode and remote SCP mode.
3.3.5.5 Remote System Mode - This mode can be thought of as the logical one of the syscon and the modem
terminal. The remote system mode can be entered in two ways, given that the access level is set to full. It can be
entered if the current mode is the local system mode, (meaning the CPU port is connected directly to the system
console), or if in remote SCP mode and the CONTINUE command is entered.
In this mode, the CPU is normally running the operating system and the PIO/DCH controller is connected to the
modem terminal via firmware connection. This connection is between the external DUART and the modem
UART internal to the 8031. Once connected, entering a BREAK B command sequence at the modem terminal
forces a non-maskable interrupt to CPU microcode, the modem terminal then enters the remote SCP mode.
In remote system mode, the IAC port is directly connected to the user terminal. The local system console is
reconnected to the port-B of the external DUART and echoes all modem terminal output via firmware. See
Figure 3-12 for the DRP configuration for this mode.
DGC CONFIDENTIAL - INTERNAL USE ONLY
3-33
043-003621
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