I should not have used the terms in=pulse and outpulse when talking about a T1. Our PBX is an R1 type. For Tone Set, the configuration manager for the device has available MF and PBMF. PBMF is what we normally use with other PBX/switches. To check the NetVanta's T1 port, i could use a second NetVanta and tie the two together via the T1 or I could use a second T1 port one just one NetVanta using a crossover, correct?
I don't know what PBMF is but I would try that, it may be DTMF. I don't think the TA900 is compatible with MF, few people these days are familiar with it. Also not familiar with "R1 type", is that a model number? What make, model, software? Perhaps you could ask the PBX vendor or manufacturer how to set it up for T1 E&M wink, DTMF.
If your PBX has the capability of PRI instead of robbed-bit T1 then change both the PBX and the Adtran trunk to PRI. That will simplify things and also reduce post-dial delay.