| Input Parameters | Significance |
| DtvLong len_max | maximum length of the message windows [0 = to top menu row] |
| Output Parameters | Significance |
| no | - |
| Return Code | Significance |
| 0 | no error |
| 1 | wrong value |
The maximum length of the message windows limits the number of messages that can be displayed below each other. Each message occupies one row.