# Number of lines

Source: https://developer.avalara.com/products/communications/integration-guides/communications-integration/zrt1851117948464/

Guide: Communications

# Number of lines

**Element type: Required for Voice**

**Enpoints/models used:** [LineItem](https://developer.avalara.com/api-reference/communications/v2/models/LineItem/)

Your integration must provide a method for specifying the number of lines being serviced for this line item. This is used for summarizing charges and can be specified using the `line` field in the [LineItem](https://developer.avalara.com/api-reference/communications/v2/models/LineItem/) model. This value defaults to 0.

There are some basic rules that your integration needs to follow when summarizing charges. For a given T/S pairing mapped to a particular transaction:

1.  Avalara will calculate tax on charges (which can be summarized usually; but take note of access charges)
2.  Avalara will calculate tax on minutes (which can be summarized)
3.  Avalara will calculate tax on lines (which can be summarized)

If a T/S pair requires a Charge, Minutes, or Lines, Avalara will only use the required inputs in the tax determination. You can pass information in all three attributes, but only the "Required" input will be used for tax determination.

You can also calculate tax on an invoice that requires no usage inputs. This relies solely on the T/S pair as input to make the tax assessment. (This is the 19/43 example.)

Note

In the case of Access Charges (ServiceType: 6) T/S pairs, you must use the `qty` attribute if you don’t list each Access Charge as a separate transaction.

**View example**:

```
"itms": [
  {
    "ref": "Reference Code for Line Item",
    "from": {
      // Location
    },
    "to": {
      // Location
    },
    "chg": 100,
    "line": 0,
    "loc": 0,
    "min": 0,
    "sale": 1,
    "plsp": 0,
    "incl": false,
    "pror": 0,
    "proadj": 0,
    "tran": 19,
    "serv": 6,
    "dbt": false,
    "adj": false,
    "adjm": 0,
    "disc": 0,
    "opt": [
      {
        // Key Value Pair
      }
    ],
    "prop": 0,
    "bill": {
      // Location
    },
    "cust": 0,
    "lfln": false,
    "date": "2018-09-23T20:31:53.452Z",
    "qty": 1,
    "glref": "General Ledger Reference"
  }
] 
```