0049-1200-XXX RM16M – USER’S GUIDE 12/29/2010
Rev. C
Page 10
of
27
TELEPHONE LINE INTERFACES
The Data Shelf is FCC certified for connection to the dial-up Public Switched Telephone Network
(PSTN). The following sections describe the standard and optional ways for connecting to the
communications line.
Modular Jack Connectors
The standard Data Shelf back panel has 16 8-pin modular jacks, one for each modem. These
jacks provide the interface for connecting individual modems to the telephone line. Each 8-pin
jack has contacts that are used in various combinations depending on the type of service
installed. Leased-line modems, by comparison, have four contacts: a transmit pair and a receive
pair.
For a description of the modular jack functions, refer to Table C-1 in Appendix C.
Optional Backplanes for Dial Backup Connections
Two optional Data Shelf backplanes are available for use with dial backup modems. These
backplanes provide either modular or mass termination jacks for both dial-up and leased line
telephone line connections. Figure 1-4 and Figure 1-5 show examples of these backplanes.
Modems with dial backup capability can switch to a dial-up line if the leased line fails. For this
reason, both the TELSET/LL and TELCO connections must be made. If the option is not used,
connect the modem to the appropriate service, either leased line or dial-up. If standard modems
(no dial backup capability) are installed they are limited to connection to the TELCO only.
For a description of the modular jack functions, refer to Table C-1 in Appendix C.
NOTE:
Telco jack pin functions are identical for both standard and dial backup
modems. Similarly, DTE connectors are the same as for standard modems.
INSTALLING and REMOVING POWER MODULES
Power modules generate power that is bused to the 16 modem edge connectors on the recessed power
bus. Power modules are available in AC and DC versions.
AC Power Module
The AC power module is a 2-slot module designed for the RM16M VAC-R Data Shelf. The
RM16M VAC-R Data Shelf can hold a maximum of one AC power module.
The AC power module consists of:
•
Two transformers (one for slots 1 through 8 and the other for slots 9 through 16)
•
Two push-button circuit breaker switches on the front panel
