Convert PBM Icons to Nokia Smart Messaging Files with pbmtonokia

You will finish with a repeatable conversion from a black-and-white PBM image to one of pbmtonokia's Nokia Smart Messaging formats: uploadable hexcode, or a binary .nol, .ngg or .npm file. The examples use the installed Netpbm 11.5.2 build, packaged here as netpbm 2:11.05.02-1.1build1.

Allow about fifteen minutes. You need a shell, a readable PBM file and enough space for the output. These conversions normally need no elevated privileges. Do not use sudo unless your input directory is deliberately restricted, and do not overwrite the only copy of an image or a previously useful output.

1. Check the installed command

Confirm which executable is being used and record its Netpbm version. This is a read-only checkpoint:

$ command -v pbmtonokia
/usr/bin/pbmtonokia
$ pbmtonokia --version
pbmtonokia: Using libnetpbm from Netpbm Version: Netpbm 11.5.2
pbmtonokia: Built from source dated 2024-03-31 09:09:47
pbmtonokia: Built by Debian

Your build date and packaging line may differ. The useful check is that the command is the expected Netpbm program and that it runs. The installed manual documents six format names: HEX_NOL, HEX_NGG, HEX_NPM, NOL, NGG and NPM.

2. Check the PBM before converting it

Inspect the input path without changing it. Replace the placeholder with your own file:

$ INPUT='/path/to/icon.pbm'
$ test -r "$INPUT" && echo 'input is readable'
input is readable
$ file "$INPUT"
/path/to/icon.pbm: Netpbm image data, portable bitmap, ASCII text

PBM is a one-bit image format, so this tool is not the right choice for greyscale or colour data. The program accepts PBM images with up to 255 rows or 255 columns, but the Nokia formats have smaller useful dimensions. The documented valid sizes are 72 by 14 or 78 by 21 for operator logos and group graphics, and 72 by 28 for picture messages. Check the image dimensions with a Netpbm tool available on your system, or inspect the PBM header before proceeding.

Checkpoint: keep the original PBM unchanged. The converter reads it and writes its result to standard output; it does not edit the source image.

3. Produce uploadable operator-logo hexcode

The default format is HEX_NOL, an uploadable Nokia Operator Logo hex string. Make the choice explicit in scripts and redirect it to a new destination:

$ OUTPUT='operator-logo.hex'
$ pbmtonokia -fmt HEX_NOL -net 62F210 "$INPUT" > "$OUTPUT"
$ test -s "$OUTPUT" && echo 'hex output written'
hex output written
$ head -c 64 "$OUTPUT"; echo
0605041582000062F2100008040155AA3CC3

The exact hex string depends on the image. The example network code, 62F210, is the manual's default and represents a six-hex-digit operator network code. Supply the code required by the operator logo you are creating; do not treat the default as a universal network identity.

Shell redirection truncates an existing destination before the program has succeeded. If operator-logo.hex already contains something you need, choose another name or make a deliberate backup first. A safe replacement pattern is:

$ pbmtonokia -fmt HEX_NOL -net 62F210 "$INPUT" > operator-logo.hex.new
$ test -s operator-logo.hex.new
$ mv operator-logo.hex.new operator-logo.hex

If conversion fails, remove only the incomplete operator-logo.hex.new after checking it is the file you created. The original output remains in place. If the first command wrote directly to an old path, recovery depends on your backup or filesystem snapshots; the program has no undo operation.

4. Choose the message type and output container

Use HEX_NGG for uploadable Nokia Group Graphic hexcode and HEX_NPM for uploadable Nokia Picture Message hexcode. A picture message may include text, up to the format's 120-character limit:

$ pbmtonokia -fmt HEX_NGG "$INPUT" > group-graphic.hex
$ pbmtonokia -fmt HEX_NPM -txt 'Meet at 18:00' "$INPUT" > picture-message.hex
$ wc -c group-graphic.hex picture-message.hex
  30 group-graphic.hex
  74 picture-message.hex
 104 total

The byte counts are examples from a small test image and will vary. Check that each file is non-empty and that the picture-message text is intentional. -txt defaults to no text; it is not a filename option.

The non-hex formats write binary files suitable for the older desktop editor formats documented by Netpbm. Redirect them with matching extensions:

$ pbmtonokia -fmt NOL "$INPUT" > operator-logo.nol
$ pbmtonokia -fmt NGG "$INPUT" > group-graphic.ngg
$ pbmtonokia -fmt NPM -txt 'Meet at 18:00' "$INPUT" > picture-message.npm
$ file operator-logo.nol group-graphic.ngg picture-message.npm
operator-logo.nol:      data
group-graphic.ngg:      data
picture-message.npm:    data

Do not use head, a text editor or a terminal display as a binary-file validator. In a controlled test, the files begin with format markers such as NOL, NGG and NPM, but file may simply call them data. The separate HEX_* forms are easier to inspect because they are printable text.

5. Diagnose failures without changing the source

A missing or unreadable input is usually a path or permission problem. Check it directly:

$ ls -l "$INPUT"
$ test -r "$INPUT" && echo readable
readable

If the command reports that the first byte is not a Netpbm magic number, the input may be empty or may not be a PBM. Recheck the file with file and keep the original for inspection. Do not rename a PNG or PGM to .pbm and expect the converter to accept it.

If the result is rejected by a Nokia handset or editor even though the command exits successfully, check the dimensions and format choice first. A successful exit means that pbmtonokia generated output; it does not prove that the image dimensions match the receiving device's requirements. For an operator logo, verify both the six-digit network code and the selected logo dimensions. For a picture message, verify the text length and use HEX_NPM or NPM as required by the receiving software.