Switching Network of of Digital Telephone Switching Systems
The switching network shall be fully digital with a combination of time space time switching and either a duplicated network (redundancy) or equivalent arrangement to avoid significant interruption of service.
5.18.2 PCM Digital Trunks
The Network will terminate PCM lines directly, and provide for Saudi Aramco a direct digital interface via a 2048 kb/s (E1) PCM signals.
5.18.3 Inserted Connection Loss
The switch shall allow the insertion of digital loss to provide uniformity in built-up connections. The loss must be inserted via software and not by digital pads.
5.18.4 Trunk Interface
The exchange shall be equipped with digital trunk interface and when it is required with Common Channel Signaling (CCS) trunk interface.
a) Digital Trunks
Digital trunks shall be connected directly to the switching network via a digital transmission interface unit.
The digital transmission interfaces of the switching unit shall perform the following basic functions:
1. Generation of an outgoing frame code.
2. Alignment of incoming and switching frames.
3. Polar conversion and rate conversion between line and switching network.
4. Alarm processing, including incoming carrier group, alarm insertion, etc.
5. Hunting during reframe at a short time.
6. Office signal extraction and insertion.
7. Jitter elimination.
8. Outgoing signal equalization.
b) Common Channel Signaling (CCS) Trunks
The CCS trunks used for interoffice call connection shall be provided and connected to the switching network, when the common channel signaling system is used with the exchange.
c) Remote Line Switch (RLS) Interface
The RLS shall be connected directly to the switching network via a digital transmission interface unit provided at the host exchange. Interface between the remote and host switches shall meet ITU-T G.732. The RLS interface will be standardized for only 2048 kb/s (E1) PCM signals.