{
	"jsonrpc": "2.0",
	"method": "call",
	"params": {
		"model": "ir.attachment",
		"fields": ["name", "url", "type", "create_uid", "create_date", "write_uid", "write_date"],
		"domain": [
			["res_model", "=", "project.task"],
			["res_id", "=", 14],
			["type", "in", ["binary", "url"]]
		],
		"context": {
			"lang": "en_US",
			"tz": "Europe/Brussels",
			"uid": 1
		},
		"offset": 0,
		"limit": false,
		"sort": ""
	},
	"id": 3410721
}

{
	"jsonrpc": "2.0",
	"id": 3410721,
	"result": {
		"records": [{
			"create_uid": [1, "Administrator"],
			"create_date": "2014-10-31 09:40:35",
			"name": "Screenshot_2014-10-30-15-44-13",
			"url": false,
			"write_uid": [1, "Administrator"],
			"write_date": "2014-10-31 09:40:35",
			"type": "binary",
			"id": 220
		}],
		"length": 1
	}
}

Link generation:

model	ir.attachment
field	datas
filename_field	name
id	220
t	1414748538735

http://146.185.190.210:8069/web/binary/saveas?model=ir.attachment&field=datas&filename_field=name&id=220&t=1414748538735