The design is the shape and configuration of a telephone base as shown in the accompanying drawings. The broken lines are for illustrative purposes only and form no part of the design.Figures are included in which:Figure 1 is a perspective view of a telephone base according to a first variant of the design;Figure 2 is a front elevational view of the telephone base of Figure 1;Figure 3 is a rear elevational view of the telephone base of Figure 1;Figure 4 is a left side elevational view of the telephone base of Figure 1;Figure 5 is a right side elevational view of the telephone base of Figure 1;Figure 6 is a top plan view of the telephone base of Figure 1;Figure 7 is a bottom view of the telephone base of Figure 1;Figure 8 is a perspective view of a telephone base according to a second variant of the design;Figure 9 is a front elevational view of the telephone base of Figure 8;Figure 10 is a rear elevational view of the telephone base of Figure 8;Figure 11 is a left side elevational view of the telephone base of Figure 8;Figure 12 is a right side elevational view of the telephone base of Figure 8;Figure 13 is a top plan view of the telephone base of Figure 8;Figure 14 is a bottom view of the telephone base of Figure 8;Figure 15 is a perspective view of a telephone base according to a third variant of the design;Figure 16 is a front elevational view of the telephone base of Figure 15;Figure 17 is a rear elevational view of the telephone base of Figure 15;Figure 18 is a left side elevational view of the telephone base of Figure 15;Figure 19 is a right side elevational view of the telephone base of Figure 15;Figure 20 is a top plan view of the telephone base of Figure 15;Figure 21 is a bottom view of the telephone base of Figure 15;Figure 22 is a perspective view of a telephone base according to a fourth variant of the design;Figure 23 is a front elevational view of the telephone base of Figure 22;Figure 24 is a rear elevational view of the telephone base of Figure 22;Figure 25 is a left side elevational view of the telephone base of Figure 22;Figure 26 is a right side elevational view of the telephone base of Figure 22;Figure 27 is a top plan view of the telephone base of Figure 22; andFigure 28 is a bottom view of the telephone base of Figure 22.