The POS895 does not answer Epson's ENPC broadcast, so PrintServer never
registers it and every job for it fails with "Printer not found". The
feasibility notes listed the vendor's own discovery protocol as unknown
and expected a packet capture to recover it, which is what this does.
Captured pktmon traffic while running the vendor EasySet tool on the
printer's segment. The protocol is:
query UDP broadcast 255.255.255.255:3289, sent FROM source port 9100
53 50 52 54 2D 49 6E 66 6F 72 00 00 0D "SPRT-Infor" 00 00 0D
reply from <printer>:3289 back to <querier>:9100, 39 ASCII bytes
"28-0e-8b-3d-ca-f1 2608120478"
MAC, 17 chars 12 spaces serial, 10 chars
The printer's address is the reply's source IP. Pos895Test now sends this
probe and parses the replies; run against the real printer it returns the
same MAC and serial the vendor tool got, so the reimplementation matches.
Two useful side effects. Port 3289 is the same UDP port ENPC uses, so a
composite IDiscoveryService can share one socket. And the querying machine
and the printer sat in different /24s of one flat segment, so the /24 TCP
sweep the notes originally preferred would have missed this printer.
The print test is commented out at the bottom of Program.cs rather than
deleted; it confirmed Font A is 48 columns and that GS ! magnification
works at width 1x/2x/3x with height 2x.
Notes updated: the discovery work item is no longer the largest one, the
compatibility table records DLE EOT and GS ! as confirmed and ESC d as
apparently ignored, and the answered questions are separated from the
ones still open.
Claude-Session: https://claude.ai/code/session_01E6N3P4nSZLtp4BC2LXVref
Pos895Test is a console app that drives a POS895 over TCP through the
existing EpsonPrinter class, to answer the first question in the
feasibility notes: does the printer accept our ESC/POS at all.
It builds the whole job as one byte array and sends that exact array, so
the hex listing it prints is the wire content by construction rather than
a reconstruction that can drift. Current job prints a "|---" column ruler
at 48/width characters per row for width magnifications 1x, 2x and 3x at
double height, so every row should end at the same right margin.
Confirmed against the hardware so far:
- DLE EOT 1..4 are answered and follow the Epson bit layout exactly, with
the 0x12 fixed bits set on every reply, so EpsonPrinterStatus parses
this printer unmodified.
- Font A is 48 columns on the 576-dot line, as the manuals claim.
- GS ! magnification works, verified at width 1x/2x/3x and height 2x.
- ESC ! 0x00 selects Font A.
Not yet confirmed: Font B and its claimed 64 columns, the GS I 1 model
byte, ESC d n feed (this firmware appears to ignore it, hence the literal
LF bytes before the cut), code page 18 being CP852, and raster graphics.
Deliberately does not call GS I 1: the model byte is still an open
unknown and a smoke test must not be able to fail on one.
All settings are constants at the top of Program.cs; there are no
arguments.
Claude-Session: https://claude.ai/code/session_01E6N3P4nSZLtp4BC2LXVref
