ZyXEL P-794H User Guide - Page 222
Table 108, SHDSL Configuration
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Chapter 18 SHDSL Configuration The following table describes the labels in this screen. Table 108 SHDSL Configuration LABEL Unit ID WireMode DESCRIPTION You can set the P-794H to work in CPE or CO mode. The wire mode allows you to physically bundle two SHDSL ports into a single 4-wire connection. The 4-wire mode is described in ITU-T G.991.2. You can use it to connect to SHDSL modems or routers that also support 4-wire mode. PAM Mode MinLineRate MaxLineRate PSD Annex Select the wire mode and wire pair from the drop-down list. Select the type of Trellis Coded Pulse Amplitude Modulation (TC-PAM) the P-794H uses from the drop-down list. This assigns a specific DSL profile to one or more ports. Type the minimum upstream transfer rate for this profile. The SHDSL connection will not come up if you set this higher than the lowest speed the link can reach. Type a maximum transfer rate for this profile. Configure the PSD as SYMMETRIC or ASYMMETRIC. Select the region setting. Select ANNEX_A to use DSL over POTS. Line Probe Select ANNEX_B to use DSL over ISDN. The SHDSL line card and subscriber modem use line probes to determine the best possible transmission rate. This is used in rate adaptation. Select LP_ENABLE to enable this function. PMMS PBO Select LP_DISABLE to disable the line probe and have the system skip the rate adaptation phase to shorten connection set up time. The PMMS (Power Measurement Modulation Session) mode specifies how the target noise margin value is acquired. Select true to enable it. This field sets the power backoff setting on the specified SHDSL port(s). Power backoff calculates how much power is needed for the connection. This allows the STU-C and STU-R to use only enough power for the port's maximum transmission rate (configured in the SHDSL profile). You can normally just leave the default setting (PBO_NORMAL), you only need to use this command if the STU-R does not support EPL (Estimated Power Loss) or you need to configure the port to use a specific power backoff setting. Select PBO_NORMAL to have each end calculate an EPL and use it in determining a power backoff value for the other end to use. PBOValue Target Margin Select PBO_FORCED to have the STU-C calculate an EPL and use it in determining the power backoff values for both ends. This can be used when the STU-R device does not support EPL. Specify the power backoff value measured in decibel (dB). Enter the target margin in this field. 222 P-794H User's Guide
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