if the trouble goes away with the modem off, then make sure that EVERYTHING EXCEPT the modem is filtered, this would include the alarm system, fax machine, satellite boxes, phones, etc...
1	if	if	SCONJ	IN	_	4	mark	4:mark	_
2	the	the	DET	DT	Definite=Def|PronType=Art	3	det	3:det	_
3	trouble	trouble	NOUN	NN	Number=Sing	4	nsubj	4:nsubj	_
4	goes	go	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	12	advcl	12:advcl:if	_
5	away	away	ADV	RB	_	4	advmod	4:advmod	_
6	with	with	SCONJ	IN	_	9	mark	9:mark	_
7	the	the	DET	DT	Definite=Def|PronType=Art	8	det	8:det	_
8	modem	modem	NOUN	NN	Number=Sing	9	nsubj	9:nsubj	_
9	off	off	ADV	RB	_	4	advcl	4:advcl:with	SpaceAfter=No
10	,	,	PUNCT	,	_	12	punct	12:punct	_
11	then	then	ADV	RB	PronType=Dem	12	advmod	12:advmod	_
12	make	make	VERB	VB	Mood=Imp|VerbForm=Fin	0	root	0:root	_
13	sure	sure	ADJ	JJ	Degree=Pos	12	xcomp	12:xcomp	_
14	that	that	SCONJ	IN	_	20	mark	20:mark	_
15	EVERYTHING	everything	PRON	NN	Number=Sing|PronType=Tot	20	nsubj:pass	20:nsubj:pass	_
16	EXCEPT	except	ADP	IN	_	18	case	18:case	_
17	the	the	DET	DT	Definite=Def|PronType=Art	18	det	18:det	_
18	modem	modem	NOUN	NN	Number=Sing	15	nmod	15:nmod:except	_
19	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	20	aux:pass	20:aux:pass	_
20	filtered	filter	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	13	ccomp	13:ccomp	SpaceAfter=No
21	,	,	PUNCT	,	_	12	punct	12:punct	_
22	this	this	PRON	DT	Number=Sing|PronType=Dem	24	nsubj	24:nsubj	_
23	would	would	AUX	MD	VerbForm=Fin	24	aux	24:aux	_
24	include	include	VERB	VB	VerbForm=Inf	12	parataxis	12:parataxis	_
25	the	the	DET	DT	Definite=Def|PronType=Art	27	det	27:det	_
26	alarm	alarm	NOUN	NN	Number=Sing	27	compound	27:compound	_
27	system	system	NOUN	NN	Number=Sing	24	obj	24:obj	SpaceAfter=No
28	,	,	PUNCT	,	_	27	punct	27:punct	_
29	fax	fax	NOUN	NN	Number=Sing	30	compound	30:compound	_
30	machine	machine	NOUN	NN	Number=Sing	27	list	27:list	SpaceAfter=No
31	,	,	PUNCT	,	_	27	punct	27:punct	_
32	satellite	satellite	NOUN	NN	Number=Sing	33	compound	33:compound	_
33	boxes	box	NOUN	NNS	Number=Plur	27	list	27:list	SpaceAfter=No
34	,	,	PUNCT	,	_	27	punct	27:punct	_
35	phones	phone	NOUN	NNS	Number=Plur	27	list	27:list	SpaceAfter=No
36	,	,	PUNCT	,	_	27	punct	27:punct	_
37	etc	etc.	NOUN	FW	Abbr=Yes|Number=Sing	27	list	27:list	SpaceAfter=No
38	...	...	PUNCT	.	_	12	punct	12:punct	_
