Compaq 1610 Reference Manual page 128

6. This apparatus has been approved for the following facilities:
Simple modem
Facsimile
Automatic call initiation
Detection of initial proceed indication
Detection of secondary proceed indication
Operation in the absence of proceed indication
Automatic dialing
Tone detection of busy tone, dial tone, or number
unobtainable tone
Auto clear from the call origination end
Loop disconnect (pulse) dialing
Multi-frequency (tone) dialing
7. Any other usage will invalidate the approval of the apparatus,
if as a result it then ceases to conform to the standards against
which approval was granted.
8. This equipment may not necessarily provide for the effective
hand-over of a call to or from a telephone connected to the
same line.