These ushort values appear in legacy tooling and in device negative acknowledgements. The canonical definitions live in SdcpMessageBuffer (SDCP_ERR_* constants). A smaller curated set is duplicated in SdcpErrorCodes.
The PVM-740 Interface Manual for Programmers excerpt (ManualsLib) states that on an NG response the payload carries the original item number plus a 1-byte category and 1-byte error code, and mentions a communication family (e.g. checksum / F0**h-style encodings in the excerpt). Map captured bytes to the SDCP_ERR_* / 0xF010 checksum constant and neighbors in SdcpMessageBuffer — see also pvm-740-programmer-manual-synthesis.md § SDCP error response.
| Decimal | Hex | Name in source |
|---|---|---|
| 257 | 0x0101 | SDCP_ERR_INVALID_ITEM |
| 258 | 0x0102 | SDCP_ERR_INVALID_ITEMREQ |
| 259 | 0x0103 | SDCP_ERR_INVALID_LENGTH |
| 260 | 0x0104 | SDCP_ERR_INVALID_DATA |
| 273 | 0x0111 | SDCP_ERR_SHORT_DATA |
| 288 | 0x0120 | SDCP_ERR_INVALID_SUB_CMD |
| 289 | 0x0121 | SDCP_ERR_INVALID_SUB_CMD_DATA |
| 290 | 0x0122 | SDCP_ERR_PASSWORD_LOCKED |
| 291 | 0x0123 | SDCP_ERR_PASSWORD_AUTHENTICATION_ERROR |
| 292 | 0x0124 | SDCP_ERR_OPERATE_CONDITION_ERROR |
| 293 | 0x0125 | SDCP_ERR_COPY_EXECUTION_ERROR |
| 294 | 0x0126 | SDCP_ERR_USER_LUT_EXECUTION_ERROR |
| 295 | 0x0127 | SDCP_ERR_CAN_NOT_CONTROL |
| 384 | 0x0180 | SDCP_ERR_NOTAPPLICABLE |
| 400 | 0x0190 | SDCP_ERR_NOTEXECUTED_ORDER_SETTING |
| 513 | 0x0201 | SDCP_ERR_DIFFCOMMUNITY |
| 4097 | 0x1001 | SDCP_ERR_INVALID_VERSION |
| 4098 | 0x1002 | SDCP_ERR_INVALID_CATEGORY |
| 4099 | 0x1003 | SDCP_ERR_INVALID_REQUEST |
| 4113 | 0x1011 | SDCP_ERR_SHORT_HEADER |
| 4114 | 0x1012 | SDCP_ERR_SHORT_COMMUNITY |
| 4115 | 0x1013 | SDCP_ERR_SHORT_COMMAND_V3 |
| 4116 | 0x1014 | SDCP_ERR_SHORT_ID_V3 |
| 4117 | 0x1015 | SDCP_ERR_SHORT_MONITORNAME_V4 |
| 4118 | 0x1016 | SDCP_ERR_SHORT_ID_V4 |
| 4119 | 0x1017 | SDCP_ERR_SHORT_COMMAND_V4 |
| 4128 | 0x1020 | SDCP_ERR_ACCESS_DENIED |
| 4129 | 0x1021 | SDCP_ERR_INVALID_ID |
| 4130 | 0x1022 | SDCP_ERR_NAME_DIFFER |
| 4131 | 0x1023 | SDCP_ERR_CANNOT_EXECUTE_SET_OPERATION |
| 8193 | 0x2001 | SDCP_ERR_NETWORK_TIMEOUT |
| 61441 | 0xF001 | SDCP_ERR_COMM_TIMEOUT |
| 61456 | 0xF010 | SDCP_ERR_COMM_CHECKSUM |
| 61472 | 0xF020 | SDCP_ERR_COMM_FRAMING |
| 61488 | 0xF030 | SDCP_ERR_COMM_PARITY |
| 61504 | 0xF040 | SDCP_ERR_COMM_OVERRUN |
| 61520 | 0xF050 | SDCP_ERR_COMM_OTHER |
| 61680 | 0xF0F0 | SDCP_ERR_COMM_UNKNOWN |
| 61712 | 0xF110 | SDCP_ERR_NVRAM_READ |
| 61728 | 0xF120 | SDCP_ERR_NVRAM_WRITE |
| 65531 | 0xFFFB | SDCP_ERR_INTERNAL_ASSERT |
| 65532 | 0xFFFC | SDCP_CLOSE_NETWORK |
| 65533 | 0xFFFD | SDCP_ERR_INTERNAL_NETWORK |
| 65534 | 0xFFFE | SDCP_ERR_INTERNAL_ERROR |
| 65535 | 0xFFFF | SDCP_ERR_INVALID_PACKET |
Return codes used by higher-level helpers (VmsCommandEngine, VmaClient) are not the same list: see MonitorProtocolCodes (Ok = 32, send/recv errors).