Telstar 1 carried a single transponder with 6390MHz uplink and 4170MHz downlink.
All the 72 ports in the small-aperture ring were ganged together to make a single receive antenna with a toroidal pattern that extended 30 degrees above/below the equator of the satellite, but had even gain as the satellite spun.
The 48 ports in the larger-aperture ring worked the same way for transmit.
The overall energy budget was amazingly marginal. The solar cells only provided 14w, feeding a 3w TWT. The satellite had to be spin stabilized (with a passive coning damper), and there was no way to aim a higher gain antenna.
Source: "A General Description of the Telstar Spacecraft", R.H. Shennum and P.T. Haury, 1963, published in NASA SP-32 p.801. See particularly Figure 4 on page 806 which shows the single transponder circuit, and section VII (pp 812-816) on antennas, which includes as Figure 6 the top image in the question and the pattern described above as Figure 7 and 8.
For more technical detail, please see "The Spacecraft Antennas", J.T. Bangert, R.S. Engelbrecht, E.T. Harkless (yes, that Harkless), R.V. Sperry and E.J. Walsh, 1963, published in NASA SP-32 p.869.