Flow : DLC ------> NODE
| Field | Type | Description | 
|---|---|---|
| nxtqptr | PTRBFHDR | Pointer to next buffer header in a queue | 
| hdreptr | PTRBFELT | Pointer to first buffer element | 
| numelts | CHAR | Number of buffer elements: 1 | 
| msgtype | CHAR | Message type: OPENMSG (0x01) | 
| srcl | CHAR | Source locality | 
| srcp | CHAR | Source partner | 
| srci | INTEGER | Source index | 
| destl | CHAR | Destination locality | 
| destp | CHAR | Destination partner | 
| desti | INTEGER | Destination index | 
| ophdr.openqual | CHAR | Open qualifier: RSPERR (0x03) | 
| ophdr.opentype | CHAR | Open type: STAT (0x11) | 
| ophdr.opresid | INTEGER | Resource identifier | 
| ophdr.operr1 | INTEGER | Error code | 
| ophdr.operr2 | INTEGER | Reserved | 
| Field | Type | Description | 
|---|---|---|
| hdreptr–>elteptr | PTRBFELT | Pointer to next buffer element (NULL is only one element) | 
| hdreptr–>startd | INTEGER | Index to start of data in this buffer element's data array - 1 | 
| hdreptr–>endd | INTEGER | Index to last byte of data in this buffer element's data array | 
| hdreptr–>dataru | CHAR[SNANBEDA] | Defined as follows, where s = startd - 1 | 
| dataru[s..s+9] | Source name | |
| dataru[s+10..s+19] | Destination name | 
The error codes are defined as follows:
| Symbolic constant | Value | Description | 
|---|---|---|
| ERLKNOTOPEN | 0x03 | Link not open | 
| ERSTATOPEN | 0x05 | Station already open | 
| ERNOCB | 0x06 | Station control blocks depleted | 
| ERINVINDX | 0x07 | Invalid link index | 
| ERMAXSTAT | 0x08 | Limit for number of stations per link reached | 
| ERDIFADDR | 0x09 | Address different from that on Request-Open-Station | 
| ERBADADDR | 0x0A | Invalid DLC address |