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COMSPHERE 3900 Series Modems
5-34 September 1998 3910-A2-GN32-40
Table 5-5
(2 of 6)
Leased Line Configuration Options
LeasedLine Rate: 19200(V32t)
Nxt 19200(V32t) 16800(V32t) 14400(V32b) 12000(V32b) 9600(V32b) 7200(V32b) 4800(V32b)
19200(TMp) 14400(TMp) 9600(TMp) 7200(TMp) 4800(TMp) 2400(TMp) 2400(V22bis) 14400(V33)
12000(V33) 9600(V29) 7200(V29) 4800(V29) 4800(V27bis) 2400(V27bis)
Leased-Line Rate. Determines the modem’s data rate and modulation scheme for operation on leased lines.
NOTE: Certain changes to this configuration option will cause the modem to reset.
H 19200(V32t), 16800(V32t), 14400(V32b), 12000(V32b), 9600(V32b), 7200(V32b), 4800(V32b)
The modem operates using V.32bis or V.32terbo modulation at the data rate selected. These
modulation schemes are available on 2-wire or 4-wire leased lines.
H 19200(TMp), 14400(TMp), 9600(TMp), 7200(TMp), 4800(TMp), 2400(TMp)
The modem operates in Trellis Multipoint mode at the data rate selected. These modulation
schemes are available on 4-wire leased lines. The 19200(TMp) modulation does not appear on
tributary modems.
NOTE: TMp control modems can accept mixed inbound rates from tributary modems. For example, one
inbound link may be configured for 14.4 kbps while another link experiencing line impairments may
be configured for 9.6 kbps. The following control/tributary rate combinations are allowed: control at
19.2 kbps, tributaries at 14.4 or 9.6 kbps; control at 14.4 kbps, tributaries at 14.4 or 9.6 kbps; control
at 9.6 kbps, tributaries at 9.6 or 7.2 kbps; control at 7.2 kbps, tributaries at 7.2 or 4.8 kbps; control at
4.8 kbps, tributaries at 4.8 or 2.4 kbps; control at 2.4 kbps, tributaries at 2.4 kbps. Tributary rates will
never exceed control rates. If tributary and control rates are equal, reducing the control rate
automatically reduces the tributary rate.
H 2400(V22bis)
This modulation scheme is available on 2-wire and 4-wire leased lines.
H 14400(V33), 12000(V33)
These modulation schemes are only available on 4-wire leased lines.
H 9600(V29), 7200(V29), 4800(V29)
These modulation schemes are only available on 4-wire leased lines.
H 4800(V27bis), 2400(V27bis)
This modulation scheme is available on 2-wire (half-duplex) and 4-wire leased lines.
NOTE: It is recommended that both modems use the same fixed data rate.
NOTE: The modem must be in Direct mode before the modulation scheme can be changed from V.32bis to
another leased-line modulation (V.33, V.29, or V.22bis). See Err Contrl Mode configuration option for
more about Direct mode. On leased lines, V.42 error control and Buffer mode are only supported by
V.32bis. An error occurs if the modem is not in Direct mode when the modulation is changed from
V.32bis.
The AT command is S-Register S44=n, where n is:
1 = 14,400 (V.32bis) 12 = 12,000 (V.33) 19 = 16,800 (V.32 terbo)
2 = 12,000 (V.32bis) 13 = 9600 (V.29) 20 = 19,200 (TMp)
3 = 9600 (V.32bis) 14 = 7200 (V.29) 21 = 14,400 (TMp)
4 = 7200 (V.32bis) 15 = 4800 (V.29) 22 = 9600 (TMp)
5 = 4800 (V.32bis) 16 = 4800 (V.27bis) 23 = 7200 (TMp)
6 = 2400 (V.22bis) 17 = 2400 (V.27bis) 24 = 4800 (TMp)
11 = 14,400 (V.33) 18 = 19,200 (V.32 terbo) 25 = 2400 (TMp)