AT&T DS1/DMi/ISDN-PRI Generic 1 DS1/DMI-BOS, Operating Mode, Supported Port Types, Tie Trunk

6-4PORT TYPES/INSTALLATION COMPATIBILITIES

Although the D4-channel bank is compatible with other devices using D4 standards, its most frequent application (from this document’s perspective) is as the interface between a DIMENSION® and DS1 or T1 facilities. The physical connections from the D4 to the switch are identical to connections used in any 4-wire analog tie trunk connection. The 4-wire E&M-ER tie trunk should be used because these units include variable attenuators in the range between 0 and 25.5 dB. Therefore, external attenuator pads are not required. Since both analog and digital tie trunks are involved in the end-to- end link, the end-to-end transmission facilities (called a combination tie trunk).

GENERIC 1 DS1/DMI-BOS

The operating mode and supported port types for Generic 1 DS1/DMI-BOS are described next.

Operating Mode

Except for the spare slot adjacent to the pack, there are no special slot or option strap considerations for Generic 1 DS1/DMI, as with Generic 2. The TN722, TN722B, and TN767 plug into any normal port slot in the system.

Supported Port Types

The TN722 and TN722B only emulate tie-trunk signaling. That is, they provide 2-state signaling (on-hook/off-hook signaling). Two categories of trunk types perform 2-state signaling: tie trunks and DMI trunks.

The TN767 circuit pack provides CO in addition to tie and DMI trunk types. That is, it provides 4- state signaling (on-hook/off-hook signaling as well as ringing and no-ringing indication, and reverse battery).

NOTE: No restrictions are placed on the type of framing, signaling, or line-coding options used with any of the port types. However, take care to assure that the interface options are compatible with the distant endpoint (D4-channel banks are not now compatible with 24th- channel signaling; most D4-channel banks do not support ESF framing).

Tie Trunk

Generic 1 DS1/DMI tie trunks appear to the switch software as a TN760B analog tie trunk. Therefore, things that can be administered for a digital tie trunk can also be administered for an analog tie trunk (except for alternate voice/data (AVD) common-type trunks).

A tie trunk port presents an interface of a channel unit requiring tie trunk signaling to a far end D4- channel bank. Since six types of tie-trunk channel units use the same digital signaling format, there may not be a one-to-one relationship between a DS1/DMI tie-trunk port and the channel unit on which it terminates at a channel bank. The six types of channel units are type I, II, and III 4-wire E&M, and type I, II, and III 2-wire E&M. While these channel units have the same digital