Total Control MP/16, Operator'S Manual

Page: 84 / 182

4-6 Cellular
Cellular
NOTE:
Cellular features are only available if you purchased
cellular modems with the MP/16. For more information on the
purchase of cellular support, please contact your distributor or
U.S. Robotics sales representative.
Modems with cellular support can negotiate for either of two
cellular protocols: ETC and MNP10. These protocols are designed
to combat a variety of link establishment and data transfer
problems specific to cellular calls.
This section provides guidelines for using the ETC and MNP10
cellular protocols.
Functional Description
MNP10
MNP10 modifies data transfer techniques for increased reliability
over cellular links. It uses three major strategies:
Aggressive Adaptive Packet Assembly (AAPA). Adjusts the data
packet size during data transfer in response to line conditions,
ensuring the maximum allowable packet size at all times.
Link Management Idle (LMI).
Used to monitor line conditions when
no data is being sent, and helps guard against lost connections.
Dynamic Transmit Level Adjustment (DTLA).
Changes the transmit
level “on the fly” to adapt to changing line conditions and
determine the best level for a cellular link.
DTLA is necessary only for calls across cellular links. In
answer mode, the modem detects when an incoming call is
using DTLA, and automatically activates its own DTLA. If you
are originating calls from a mobile site (cell side), the modem
must be set for
MNP10 Cellular (S60.3=1) to implement DTLA.
Non-Cellular Calls
MNP10 can be negotiated for non-cellular calls, but offers no
advantage over other protocols for those calls. MNP10 must be
disabled (S60.1=0) to originate calls under V.34, V.FC, HST, or V.32
Terbo.