Telebit T3000 Reference Manual page 94

&G(n) Guard Tone Select
Range: 0-2
Default:
0
The &G command selects the type of guard tones the
answering modem should send in V.22 or V.22bis
mode.
&G Same as &GO.
&GO No guard tones.
&G1 550 Hz guard tone.
&G2 1800 Hz guard tone.
&J(n) Jack Type Select
Range: 0-2
Default:
0
The &J command designates how the modem uses
available telco leads.
&J Same as &JO.
&JO Auxiliary telco leads disabled.
&J1 NA1 control selected.
&J2 Ml/MIC control selected.
Note:
The hardware jumpers must be configured correctly
for proper operation. Refer to Appendix B, Interlace
Description.
&L(n) Leased Line
Range: 0
or
1
Default: O
See
also: &Q, A, D,
S100, S104
Use the &L command to place the modem into a
mode of operation for use on leased lines.
AT Command Descriptions 5-19