Motorola and V.32bis, V.34-SDC manual Point-to-Point Leased Line Application with Dial Restoral

SDC Option Set 4—Sync Leased Line with Dial Restoral; No ACU (Models 3261/63/66/68)

Point-to-Point Leased Line Application with Dial Restoral

Figure 4-5shows a typical point-to-point leased line application, with SDC modems providing leased line and dial back-up for a bridge/router network. A Motorola Network Management System (NMS) is shown. This application could apply to any nodal equipment connections (e.g., bridges, routers, or X.25 PADs).

With the modem’s integral restoral capabilities, if leased circuit operation is dis- rupted, the modems restore the connection over a single dial line through the PSTN.

The modem uses the adaptive rate feature in the V.34 Auto modulation mode. This ensures maximum throughput when line quality deteriorates. If restoral criteria are met, the modem automatically reroutes data traffic through the PSTN. At that time, the modem attempts to run at its maximum rate over the dial line, and falls back to lower speeds if required. After an hour, the modem returns to the leased line.

Select SDC Option Set 4 for this application.

Note the following:

•The line configuration default of Option Set 4 is Two-Wire Leased Line.

•With Option Set 4, the modem provides the network timing (Clock=Internal).

•To specify a non-default rate at which the modem communicates with the DTE, use the DTE Rate (AT*DE). See the DTE Rate description in Appendix A.

•Select SDC Option Set 4 in both the local and remote modems, and ensure that Mode (AT*SM) is set the same in both modems.

•If operating with the Motorola 6500 PLUS that has the Link Back-Up option, set DTR=108.2 (the default is 108.1 for 6500s without the Link Back-Up option).

PSTN

To 56/64 kbps

Bridge/ Router

326XFAST					326XFAST
	SDC		33.6 kbps			SDC
		NMS		Network Management Channel

Bridge/ Router

Figure 4-5. Point-to-Point Leased Line Application with Dial Restoral—Option Set 4