The observed serial frame is identical for both tested values of I62: 02 31 0D. In ASCII terms, 31 is the character 1, while 02 and 0D are control bytes. The evidence does not establish whether CLIPPER adds both bytes as fixed protocol framing or whether another serial layer contributes them.
Interpret the captured bytes
| Hex byte | ASCII meaning | Interpretation |
|---|---|---|
02 |
STX | A start-of-text control byte appears before the payload. Its source is not identified by the available evidence. |
31 |
1 |
This is the payload requested by SENDS “1”. |
0D |
CR | A carriage-return control byte appears after the payload. |
The byte capture therefore shows a framed message: STX, the requested character, and CR. It does not show that SENDS failed to transmit the payload.
Why the I62 test is inconclusive
The quoted documentation describes Turbo PMAC behavior: one I62 value terminates messages with a carriage return, while the other suppresses it and requires SEND^M when a carriage return is wanted. The tested device is identified as a CLIPPER board, but the evidence does not confirm that this Turbo PMAC description applies to its firmware, command variant, or selected communications port.
Because both tests produced exactly 02 31 0D, the capture does not demonstrate any effect from changing I62. It also cannot distinguish among an unsupported setting, a setting that does not govern SENDS on this target, or framing inserted elsewhere in the COM3 path.
Isolate the source of 02 and 0D
- Capture COM3 as raw hexadecimal data and repeat the two programs separately, ensuring that each
I62assignment has executed before its correspondingSENDScommand. - Read back
I62after each assignment. If the returned value does not change, resolve the assignment or persistence problem before evaluating serial framing. - Confirm that the cited Turbo PMAC documentation matches the exact CLIPPER firmware and that
I62governs the port and send command being tested. - Check the receiver, communications driver, and any intermediate serial interface for framing or terminator insertion. Suppressing
02requires identifying the layer that adds STX; the supplied evidence names no CLIPPER setting for it.
Verify the correction
After changing the applicable transmitter or communications-layer setting, repeat the raw-byte capture. Success requires a frame containing only 31 when sending the character 1. If 02 or 0D remains, record which byte persists and continue tracing that specific byte through the controller, driver, and receiver path.
FAQ
What does 02 31 0D mean on a serial capture?
02 is STX, 31 is the ASCII character 1, and 0D is CR. The capture contains one payload byte surrounded by control bytes.
Why does I62=1 still produce 0D on CLIPPER?
The same 0D was captured with I62=0 and I62=1. Verify the value by reading it back, then confirm that the Turbo PMAC description applies to the exact CLIPPER firmware, COM3 path, and SENDS command.
How do I suppress 02 from CLIPPER serial output?
The evidence identifies no setting that suppresses 02. Determine whether STX originates in the controller, communications driver, intermediate interface, or receiver before changing configuration.