LaserJet 400 M401dn No Bi-Directional Communication

[dansdaduk]

>> ... How do I know if my printer supports PJL or PML? ...

I don't think that there is any direct method of checking this.

An indirect method would be to try sending commands in those languages to the printer port and observing the results, but this is not that simple a task - you may need to set up a connection with read/write functions (to enable replies to be read on a 'back channel'), but I've only ever done this successfully on a network connection.

Havings said that, note:

• Most LaserJet printers (going back to LaserJet III and perhaps even earlier), except for the cheap 'host-based' ones, support Printer Job Language, although they won't all support all of the possible PJL commands.
• Most modern LaserJet printers probably also support Peripheral Management Language , but there is little publically available documentation on this language.
• if you 'capture' and analyse the output of modern printer drivers, you'll probably see that the 'job header' contains a number of PJL commands before entry is made to the required Page Description Language (usually PCL5 or PCL XL or PostScript) to render the printed pages; it may even be the case that some PJL commands contain embedded PML commands; for example, analysis of the start of an old sample LJ M475 print job:

Offset: dec  Type                   Sequence          Description
-----------  ---------------------  ----------------  ----------------------------------------------------

0000000000   PCL Parameterised      <Esc>%-12345X     Universal Exit Language (UEL)
             Comment                                  Switch language to PJL
0000000009   PJL Command            @PJL SET           RET=ON[0a]
0000000025   PJL Command            @PJL JOB           NAME="Microsoft Word - Document1"[0a]
0000000068   PJL Command            @PJL SET           STRINGCODESET=UTF8[0a]
0000000096   PJL Command            @PJL COMMENT       "HP LJ300-400 color MFP M375-M475 PCL 6 (0.3.1553
                                                      .12262); Windows 7 Professional 6.1.7601.1; Unidrv
                                                       0.3.7601.17514"[0a]
0000000225   PJL Command            @PJL COMMENT       "Username: chris; App Filename: Microsoft Word - 
                                                      Document1; 9-20-2012"[0a]
0000000309   PJL Command            @PJL SET           JOBATTR="JobAcct1=chris"[0a]
0000000343   PJL Command            @PJL SET           JOBATTR="JobAcct2=CHRIS"[0a]
0000000377   PJL Command            @PJL SET           JOBATTR="JobAcct3=chris"[0a]
0000000411   PJL Command            @PJL SET           JOBATTR="JobAcct4=20120920192359"[0a]
0000000454   PJL Command            @PJL SET           JOBATTR="JobAcct5=4c776222-42a3-44c1-b8ee-81b41e9
                                                      92eaa"[0a]
0000000519   PJL Command            @PJL SET           JOBATTR="JobAcct6=Print driver host for 32bit app
                                                      "[0a]
0000000579   PJL Command            @PJL SET           JOBATTR="JobAcct7=splwow64.exe"[0a]
0000000620   PJL Command            @PJL SET           JOBATTR="JobAcct8=chris"[0a]
0000000654   PJL Command            @PJL SET           JOBATTR="JobAcct9="[0a]
0000000683   PJL Command            @PJL DMINFO        ASCIIHEX="0400040101020D1010011532303132303932303
                                                      13832333539"[0a]
             >>>>>>>>>>>>>>>>>>>>                     >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
             Comment                                  Start analysis of embedded PML string
             Comment                                  of size 50 ASCIIHEX characters (25 bytes)
01:0000000000  PML Request            0x04              SetRequest
01:0000000001  PML Data Type/Length   0x0004            Object Identifier / 4
01:0000000003           Value         0x0101020d        1.1.2.13
01:0000000007  PML Data Type/Length   0x1010            String / 16
01:0000000009           Symbol Set    0x0115            277 (= 8U)
01:0000000011           Value         0x323031..        20120920182359
             Comment                                  End analysis of embedded PML string
             Comment                                  of size 50 ASCIIHEX characters (25 bytes)
             <<<<<<<<<<<<<<<<<<<<                     <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
0000000757   PJL Command            @PJL SET           USERNAME="chris"[0a]
0000000783   PJL Command            @PJL SET           JOBNAME="Microsoft Word - Document1"[0a]
0000000829   PJL Command            @PJL SET           SEPARATORPAGE=OFF[0a]
0000000856   PJL Command            @PJL SET           ECONOMODE=OFF[0a]
0000000879   PJL Command            @PJL SET           KEEPGLOSSMODE=UNDEFINED[0a]
0000000912   PJL Command            @PJL SET           RESOLUTION=600[0a]
0000000936   PJL Command            @PJL SET           BITSPERPIXEL=8[0a]
0000000960   PJL Command            @PJL ENTER         LANGUAGE=PCLXL[0a]
             Comment                                  Switch language to PCLXL
0000000986   PCLXL Stream Header    0x292048..        ") HP-PCL XL;3;0;Comment Copyright(c) 1999 Micros"
0000001034                          0x6f6674..        "oft Corporation[0a]"
0000001050   PCLXL Data Type        0xd1                  uint16_xy
0000001051              Value       0x58025802            600 600
0000001055   PCLXL Attribute        0xf889              UnitsPerMeasure
0000001057   PCLXL Data Type        0xc0                  ubyte
0000001058              Value       0x00                  eInch
0000001059   PCLXL Attribute        0xf886              Measure
0000001061   PCLXL Data Type        0xc0                  ubyte
0000001062              Value       0x03                  eBackChAndErrPage
0000001063   PCLXL Attribute        0xf88f              ErrorReport
0000001065   PCLXL Operator         0x41              BeginSession
                            No.                       1
0000001066   PCLXL Data Type        0xc0                  ubyte
0000001067              Value       0x00                  eDefaultDataSource

[dansdaduk]

... and a bit more information about 'bidirectional communication' with the Universal Printer Drivers (albeit from a somewhat dated document😞

... and:

[KCCopyguy · Accepted solution]

Thanks for the feedback.  After numerous trips to the customers site to get FM Audit to report meter/supply levels, I was finally informed by their tech support that my model HP along with countless others do not report properly if at all when a local USB connection is used.  Here is a link of models and how they report, or don't in my case. 

ftp://ftp.fmaudit.com/customer/documents/Device_Compatibility_2016.pdf

[dansdaduk]

I wonder when that document was published, and whether or not FMAudit could have told you about this some time ago?

Anyway, at least you have an answer now.