Not sure if you absolutely require IPP ... I have had some luck
using PCL ESC sequences to select trays... I think I had to test
it to see which tray the printer really thought was 1, 2, 3, etc.

A misc note I just found on the topic:

from the HP 8150 manual (bpl08658.pdf online)

ESC & l # H

l=Ell (lower L)

#
--
0 prints or ejects current page
1 Tray 2 (first regular tray)
2 manual feed, paper
3 manual feed, envelope
4 Tray 1 (bypass feeder)
5 Tray 3 (2nd regular tray)
6 Envelope Feeder
7 Auto Select
20 Tray 4
21 Tray 5
22-69 - external trays


use like:

P&l3H\

in a setup module.

Hope this may help some.


Verne
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Verne Britton, Lead Systems Programmer voice: (304) 293-5192 x230
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