The Telecom industry adopted a standard in 2001 which utilizes Micro PDF 417 for high density information content, along with a special version of Code 39 which provides backward compatibility with existing systems.  The Code 39 symbol includes a special “link” character which indicates the presence of the Micro PDF 417 symbol to new reading systems which are programmed to recognize the new format.  This label specification is documented in a Telcordia document, GR-383-CORE.  Later, the use of Data Matrix was also adopted.
The following verifiers can be used for Telecom labels.
TruCheck Optima™For users that need to verify both linear (1D) and 2D barcodes. Multiple versions are available to your field of view and minimum x dimension requirements.
TruCheck 2D USBFor imager based verification of 2D Matrix Symbologies and small linear and/or stacked symbols, especially DataBar which is especially small.