Motorola and V.32bis - Manual (Page 87)

Configuring the Modem 4-25
Confi
guring
the Modem
Figure 4-1. Single Channel Point-to-Point Digital Link Restoral (A/B Switch)—Option Set 2
Note the following:
• With SDC Option Set 2 selected (for Motorola and non-Motorola DSU/CSUs),
the DSUs’ restoral configuration should be set to Timing=Internal.
• In this case, the 326XFAST-SDC DTE Rate must be set to a constant rate as
provided by the network (defaults of 56/64 kbps).
• Enable Option Set 2 in both the local and remote modems, and ensure that
Mode (AT * SM) is set the same in both modems.
• The SDC modem supports single channel environments only. For example, the
SDC modem can restore Port 1 only of the 35XX device.
• The 35XX device, when initiating restoral, must be set to Normal mode (as the
35XX network management channel is virtually a time division multiplexed
data stream which cannot be compressed with the SDC product).
• The SDC modem may have the ARS feature enabled. In this case, ARS
determines the link rate.
Figure 4-2 shows a configuration using an external A/B switch. Network
configuration (SDC Option Set 2) and operation is the same as with an internal
switch.
Figure 4-2. Single Channel Point-to-Point Digital Link Restoral (A/B Switch)—Option Set 2
35XX
56/64 kbps
PSTN
Router 35XX Router
To 33.6 kbps
NMS
Network Management Channel
To
56 kbps
326XFAST
SDC
326XFAST
SDC
DSU/CSU
56/64 kbps
PSTN
Router Router
To 33.6 kbps
NMS Network Management Channel
A/B A/B
To 56 kbps
DSU/CSU
326XFAST
SDC
326XFAST
SDC