Datacom DM991C, Product Manual

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Product Manual - DM991 Series V Family - 204.4092.08 29
7. STRAPS
The DM991S/SE modems present substantial differences in relation to the DM991C/CE modems as to the
configurations done through strapping, in such a way that the sub chapter 7.1 verses on the DM991S/SE
modems strapping and sub-chapter 7.2 verse on the DM991C/CE modems strapping.
7.1. DM991S/SE
7.1.1. G.703 Interface Cable Selection (E4)
Position 120: Selects the use of twisted pair, meaning it operates on the G.703 interface with 120ohms
impedance.
Position 75: Selects the use of coaxial cable, meaning it operates on the G.703 interface with 75ohms
impedance – factory standard.
7.1.2. Output Coaxial Cable Grounding (E10)
Allows the coaxial cable shield to be grounded.
Position 0-1: Connects the output coaxial cable shield to the signal ground (depends on the pinout,
configured according to: Table 12, Table 13 or Table 14).
Position 0-2: Isolated – factory standard.
7.1.3. Input Coaxial Cable Grounding (E11)
Allows the coaxial cable shield to be grounded.
Position GND: Connects the input coaxial cable shield to the signal ground (depends on the pinout,
configured according to: Table 12, Table 13 or Table 14).
Position ISOL: Isolated – factory standard.
7.1.4. G.703 Interface Pinout (E12 to E15, E27 to E30 and E44 to E47)
Dial Backup – In this option, the equipment presents the G.703 interface in the Dial Backup pins in the
screw connector block. The digital interface goes out the DB25 normally, according to the pinout
configured through its straps – factory default.
E12 to E15: position 0-2.
E27 to E30: position 0-2.
E44 to E47: position 0-2.
Make sure the strap is not on grounding position when twisted pair is used(120ohms).
Make sure the strap is not on grounding position when twisted pair is used(120ohms).