USRobotics V.34 - Manual (Page 191)

COURIER HIGH SPEED MODEMS
Additional Operations G-9
MI/MIC OPERATIONS (EXTERNAL MODEMS ONLY)
DESCRIPTION
Mode Indicate/Mode Indicate Common (MI/MIC) closure is
required by some installations whose existing hardware does
the dialing. The modems do not Auto Dial.
In these situations, the modem must be forced off hook in
Originate mode. This is done by shorting (closing) two of the
pins (not Tip and Ring) in the phone connector. The modem is
then ready to go online and accept data when it connects with
the number dialed by the system equipment.
Courier modems are shipped with MI/MIC disabled, that is, for
normal use. To set the modems for MI/MIC closure, you must
do two things: physically set jumpers on the modem’s printed
circuit board, and enable bit 5 of Register S34 (ATS34=32 or
ATS34.5=1). We recommend you then write that setting to
NVRAM as a power-on default.
Once you've set Register S34, have the system force the modem
off hook by closing the MI/MIC leads in the phone line
connector. The modem's OH (Off Hook) status light, or LED,
goes on when the modem goes off hook.
SETTING THE MI/MIC JUMPERS
You'll have to dismantle the modem case to set the two jumper
switches on the printed circuit board, as follows:
1. Power off the modem and disconnect all of its cables.
2. Turn the modem upside down. Remove the two square
vinyl feet near the back of the case, on either side of the
bottom label's DIP switch diagram. Be careful to put the
vinyl feet aside, upside down, where they won't become
stuck to another object.
3. Remove the two Phillips screws located in the wells beneath
the vinyl feet.
4. Gently pry off the plastic volume slide-switch cover.
5. Raise the back end of the case bottom until it is at about a
60° angle; lift it away from inside the front of the modem.
Put the case bottom aside.