diff --git a/code/inventory/scan.c b/code/inventory/scan.c
index c94d91c..f6ccba1 100644
--- a/code/inventory/scan.c
+++ b/code/inventory/scan.c
@@ -1,72 +1,74 @@
 /*
- * scan.c - Phase 1 barcode diagnostic for the Workabout MX integral laser.
+ * scan.c - Phase 1 barcode diagnostic: decoded laser over the serial port.
  *
- * Per the I/O Devices Reference (HC Bar Code Reader chapter): load a decoder
- * LDD (BAREAN.LDD for UPC/EAN), open the device "BAR:<slot>" (top slot is "A"
- * on the HC; the Workabout may map the top slot differently), and read with
- * p_iow(pcb, P_FREAD, buf), buf >= 256 bytes. The result is a leading byte
- * count in buf[0] (0 = unsuccessful read), buf[1] = a barcode-type character,
- * and buf[2..] = the decoded digits.
+ * The Workabout MX integral laser powered up and gave a good-read LED on
+ * TTY:D, i.e. it is a DECODED scanner that emits ASCII over the serial port -
+ * no BAR: decoder LDD needed. The earlier TTY:D read returned nothing because
+ * the port's default handshake sets P_OBEY_DSR, and the I/O Devices Reference
+ * states that if the remote device does not assert DSR, an outstanding P_FREAD
+ * is suspended. The laser does not drive DSR, so the read blocked forever.
  *
- * This build probes the likely slot letters (bare "BAR:" gave E_FILE_NAME/-38
- * because it lacks the slot letter), reports which opens, then dumps the raw
- * [count][type][data] of each scan so the exact UPC format is confirmed.
+ * This build opens TTY:D, applies a P_SRCHAR config at 9600/8/1 with P_OBEY_DSR
+ * cleared (P_IGN_CTS only, so reads are not gated on modem lines), forces DTR
+ * active, then dumps every byte of each read so the decoded UPC format is seen.
  *
  * Blocking I/O; exit via the System screen.
  */
 #include <plib.h>
-#include "bcode.h"
-
-#define NCAND 4
+#include <p_serial.h>
 
 GLDEF_C INT main(VOID)
 {
-    VOID *chan;
-    UBYTE buf[256];
-    INT   loadErr, r, i, cnt, opened;
-    UINT  k;
+    VOID    *chan;
+    P_SRCHAR ser;
+    UBYTE    buf[64];
+    UBYTE    ctrl[2];
+    INT      err, n, i;
 
-    static TEXT *names[NCAND] = { "BAR:A", "BAR:D", "BAR:B", "BAR:E" };
-
-    loadErr = bcodeLoad();
-    p_printf("load %s.LDD: %d\n\n", BCODE_LDD, loadErr);
-
-    opened = 0;
-    for (k = 0; k < NCAND; k++) {
-        r = p_open(&chan, names[k], (UINT)-1);
-        p_printf("open \"%s\": %d\n", names[k], r);
-        if (r >= 0) {
-            opened = 1;
-            break;
-        }
-    }
-
-    if (opened == 0) {
-        p_printf("\nNothing opened. Press a key to exit.\n");
+    err = p_open(&chan, "TTY:D", (UINT)-1);
+    p_printf("open TTY:D: %d\n", err);
+    if (err < 0) {
+        p_printf("Press a key to exit.\n");
         p_getch();
         return 1;
     }
 
-    p_printf("\nOpened \"%s\". Scan a barcode. System screen to exit.\n\n",
-             names[k]);
+    /* 9600 baud, 8 data bits, 1 stop, no parity; do NOT obey DSR/DCD (only
+       ignore CTS) so a scanner that leaves the modem lines idle can be read. */
+    ser.tbaud  = P_BAUD_9600;
+    ser.rbaud  = P_BAUD_9600;
+    ser.frame  = P_DATA_8;
+    ser.parity = 0;
+    ser.hand   = P_IGN_CTS;
+    ser.xon    = 0x11;
+    ser.xoff   = 0x13;
+    ser.flags  = 0;
+    ser.tmask  = 0;
+    err = p_iow(chan, P_FSET, &ser);
+    p_printf("config 9600/8/1: %d\n", err);
+
+    /* Force DTR (the scanner enable line) active. Opening already drives it,
+       but make it explicit. ctrl[0] is the read-back of input lines. */
+    ctrl[0] = 0;
+    ctrl[1] = P_SRDTR_ON;
+    err = p_iow(chan, P_FCTRL, ctrl);
+    p_printf("assert DTR: %d\n", err);
+
+    p_printf("\nScan a barcode. System screen to exit.\n\n");
 
     for (;;) {
-        /* Barcode read: buffer only, count returned in buf[0]. Blocking. */
-        r = p_iow(chan, P_FREAD, buf);
-        if (r < 0) {
-            p_printf("read status %d\n", r);
+        n = p_read(chan, buf, sizeof(buf));
+        if (n < 0) {
+            p_printf("read err %d\n", n);
             continue;
         }
-        cnt = buf[0];
-        if (cnt <= 0) {
-            p_printf("(empty read)\n");
+        if (n == 0)
             continue;
-        }
-        p_printf("cnt=%d type=%d:", cnt, buf[1]);
-        for (i = 1; i <= cnt && i < 256; i++)
+        p_printf("n=%d:", n);
+        for (i = 0; i < n; i++)
             p_printf(" %d", buf[i]);
         p_printf("  \"");
-        for (i = 1; i <= cnt && i < 256; i++)
+        for (i = 0; i < n; i++)
             p_putch(buf[i] >= ' ' ? buf[i] : '.');
         p_printf("\"\n");
     }