Problem:

Why does runcobol hang with ssh on AIX?

Resolution:

It may be a "bug" in OpenSSH. Please see the lenthy discussion here:

http://bugzilla.mindrot.org/show_bug.cgi?id=1102

Try applying the patch (http://bugzilla.mindrot.org/attachment.cgi?id=1002&action=view) mentioned in the bug and see if the problem is resolved.