Maintenance Operations Protocol
The Maintenance Operation Protocol is used for utility services such as uploading and downloading system software, remote testing and problem diagnosis. It was a proprietary protocol of Digital Equipment Corporation.
MOP frames can be one of the following commands:
| Command | Description |
| Request for assistance with dump operation. | |
| Request for next memory dump segment. | |
| Contains memory dump data. | |
| Acknowledgment of dump completion. | |
| Offer of dump/load/loop assistance. | |
| Request for system or loader | |
| Request for remote console identification. | |
| Remote console identification information. | |
| Request for communication information counters. | |
| Communication information counters. | |
| Remote console in reserved state. | |
| Release of remote console from reserved state. | |
| Poll of remote console for status. | |
| Response to remote console poll. | |
| Response to loopback request with data. |