APPENDIX C: E&M Voice/Fax Interface Module
75
C.7 Strapping
Enhanced E&M Voice/Fax Interface Card
The functions of straps E1 through E22 on the
enhanced E&M interface card (see Figure C-7) are
as follows:
1. E1 through E5. These straps are preset at the
factory to match the type of memory installed.
Do not alter them.
2. E6, E7, and E9 through E13. These straps are
used to select signaling types I, II, and V
(MX402C only).
3. Straps E8 and E17 are normally installed to
shunt out DC blocking capacitors C36 and C38.
Remove them if there are DC voltages present in
the R and R1 leads.
4. Strap E14 is used to shunt out the series resistor
in the E lead in case the loop resistance is too
high to trip the detector inside the PBX.
5. Strap E15 is used for dial-pulse correction; it
connects a 1-µF filter capacitor between the SG
lead and ground.
6. Strap E16 is used to shunt out the series resistor
in the SB lead in case the loop resistance is too
high to trip the detector inside the interface
module.
7. Straps E18 and E19 are reserved for use in
internal tests. Do not alter them.
8. Straps E20, E21, and E22 are spares.
E17
C38
E18
C36
E8
TYPE V
E14
E15
E16
E19
E20
E21
E22
E10
E9
E11
E13
E12
E7
E6
E2
E1
E5
E4
E3
S/N
TYPE II
TYPE I
Figure C-7. Where the Straps Are on the E&M Module.