Figure 8-1 secondary protector diagram – Toshiba Strata DK8 User Manual
Page 199
8-5
INSTALLATION-WIRING DIAGRAMS
SECTION 100-816-208
MARCH 1993
FIGURE 8-1
SECONDARY PROTECTOR DIAGRAM
IMPORTANT!
To protect against transient voltages and currents, secondary protectors must be installed if
there is outside wiring (Figure 8-1). These protectors, which contain fast semiconductors in
addition to fuses, shall comply with the requirements for secondary protectors for communication
circuits, UL 497A. As of October 1, 1990, the following manufacturers offer secondary
protectors that are UL listed.
,
,
,
,
,
,
,
,
,,,
,,,
,
,
,
,
,
,
,
,
,
,,,
,,,
,
,
,
,
,
,
,
,,,,
,,,,
,
,
,
,
,
,
,
,,,,
,,,,
,
QSTU
PESU
KSTU
PSTU
BUILDING #1
BUILDING #2
DK8 KSU
DK16 KSU
BASE UNIT
KCDU
PCOU
QCDU
HESB
DIGITAL OR
ELECTRONIC
TELEPHONE
DIGITAL OR
ELECTRONIC
TELEPHONE
STANDARD
TELEPHONE
OR OTHER
DEVICE
MDFB
CO LINE
Secondary protectors
DDCB
DK8 KSU
DK16 KSU
BASE UNIT
QCDU
PDKU
PEKU
PESU
KCDU
DSS
CONSOLE
(DK16 only)
219
209
208
218
207
217
206
216
205
215
204
214
203
213
202
212
201
211
200
210
220
230
231
221
222
232
223
233
224
234
225
235
226
236
237
227
228
238
229
239
249
NT1
AC
248
247
257
256
246
245
255
254
244
253
243
242
252
241
251
240
250