3Com MSR 50, MSR 30 manual 275

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Parameters dsu-mode: Specifies the FT3 (Fractional T3) DSU mode for a CT3 interface operating in FT3 mode. This keyword can be followed by 0, 1, 2, 3, and 4, as described below.

0: Specifies the Digital Link mode, where the subrate is a multiple of 300746 bps and ranges from 300 to 44210 kbps (that is, up to 147 rate levels are available).

1: Specifies the Kentrox mode, where the subrate is a multiple of 1500 kbps and ranges from 1500 to 35000 kbps. In this mode, the subrate can also be 44210 kbps, making a total of 57 subrate levels.

2: Specifies the Larscom mode, where the subrate is a multiple of 3157835 bps and ranges from 3100 to 44210 kbps (that is, up to 14 subrate levels are available).

3: Specifies the Adtran mode, where the subrate is a multiple of 75187 bps and ranges from 75 to 44210 kbps (that is, up to 588 subrate levels are available).

4: Specifies the Verilink mode, where the subrate is a multiple of 1578918 bps and ranges from 1500 to 44210 kbps (that is, up to 20 subrate levels are available).

subrate number: Specifies the subrate for the CT3 interface. The number argument ranges from 1 to 44210 (in kbps).

Description Use the ft3 command to configure a CT3 interface to operate in the FT3 mode and set the DSU mode or the subrate.

Use the undo ft3 command to restore the default.

By default, DSU mode 0 (the Digital Link mode) is adopted, and the subrate is 44210 kbps.

FT3 (Fractional T3 or Subrate T3) mode is a non-standard E3 application mode. In this mode, the subrate level setting varies with vendors. You can use the ft3 command to make the device to be compatible with devices of other vendors operating in specific FT3 DSU modes.

Note that:

■These two commands are only applicable to CT3 boards that support FT3.

■These two commands are only available in T3 mode.

■As for the ft3 subrate command, the actual subrate usually is not exactly the one set by the command. That is, after you set the subrate by using the ft3 subrate command, the CT3 interface searches the subrate levels corresponding to the DSU mode it is operating in and selects the one that is closest to that set by the command as its subrate. The device then adjusts the hardware to allow for the subrate.

■You can use the display interface serial interface-number:0 command to check the DSU mode setting, the subrate, the actual rate, and the baudrate of a CT3 interface. Note that the actual rate does not count in the overhead bits, and the baudrate is the actual T3 line rate (that is, 44736 kbps), with the overhead bits counted in.