You just need to add pagination related properties pagination : true to the detail grid options. Here is what your detailGridOptions would look like -   
this.detailCellRendererParams = {
  detailGridOptions: {
    columnDefs: [
      { field: 'callId' },
      { field: 'direction' },
      {
        field: 'number',
        minWidth: 150,
      },
      {
        field: 'duration',
        valueFormatter: "x.toLocaleString() + 's'",
      },
      {
        field: 'switchCode',
        minWidth: 150,
      },
    ],
    defaultColDef: { flex: 1 },
    pagination : true, //set pagination to true
    paginationPageSize: 5 // define page size, default is 100
  },
  getDetailRowData: function(params) {
    params.successCallback(params.data.callRecords);
  },
};
}
Attaching the example screenshot - 

Used this example