diff --git a/src/pygui/serialcomm/stream_reader.py b/src/pygui/serialcomm/stream_reader.py
index feb2aa3..198351d 100644
--- a/src/pygui/serialcomm/stream_reader.py
+++ b/src/pygui/serialcomm/stream_reader.py
@@ -7,6 +7,7 @@ import time
 from typing import Callable
 
 from pygui.backend.models.frame import Frame
+from pygui.backend.wafer.family_spec import sensor_count_for
 from pygui.serialcomm.data_parser import _convert_hex_to_temp
 
 log = logging.getLogger(__name__)
@@ -182,7 +183,7 @@ class StreamReader:
     def _run_ascii(self, initial_bytes: bytes) -> None:
         log.info("StreamReader: starting ASCII hex dump stream parsing")
 
-        valid_words = 80 if self._family_code == "X" else 244
+        valid_words = sensor_count_for(self._family_code)
         block_words = 256
         word_char_len = 4
         chars_needed = block_words * word_char_len  # total hex chars per block