Zhone Technologies, Inc. | IMACS Product Book, Version 4 | |
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| EIA RS-530 | High-speed 25 Position Interface for Data Terminal Equipment, Including Alternative 25 | |
| | Position Connector. | |
| EIA RS-366 | Interface Between Data Terminal Equipment and Automatic Calling Equipment for Data | |
| | Communication | |
| FCC Part 15 | Subpart B | |
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| UL 1950 | UL Standard for Safety of Information Technology Equipment | |
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| CE EN 500 81-1 | Electromagnetic compatibility generic emission standard Part 1 Residential, | |
| | commercial and light industry | |
| CE EN 500 82-1 | Electromagnetic compatibility generic immunity standard Part 1 Residential, | |
| | commercial and light industry | |
| CE EN 60 950/A2 | Safety of information technology equipment including electrical business | |
| | equipment | |
| BellCore GR-63-CORE | Network Equipment-Building System (NEBS) Requirements: Physical Protection | |
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2. SRU Card
The 822060/822161 SRU Card allows synchronous or asynchronous connections of up to ten RS-232, low-speed and medium-speed (300 bps to 38.4 kbps) data terminals to the integrated access system. Since an SRU port does not require a complete 64Kbps time slot, the Sub-Rate card allows the multiplexing of a number of devices into a single, subdivided time slot on a WAN card. SRU card ports can also be multiplexed with voice traffic on an ADPCM engine. The 822060 accesses user buses A & B, and the 822161 SRU accesses user buses C & D. The 822061 SRU has equivalent functions as the 822060 with the exception of Idle Pattern changes. The 822460 SRU has 4 RS-422 ports that support synchronous and/or asynchronous connections from 300 bps to 38.4 Kbps. The Low Delay SRU provides 10 RS-232E ports that support synchronous and/or asynchronous V.14 operations. The sub-rate multiplexing is performed by hardware instead of software.
Each RS-232 port can be independently programmed for synchronous (including HDLC) or asynchronous operation. Synchronous operation is available at speeds of 2.4 Kbps up to 38.4 Kbps while for asynchronous the range is 300 bps up to 38.4 Kbps. Each synchronous port can receive timing from either the DTE device or the system clock. If the DTE supplies the transmit clocking, it must be synchronized with the system clocking source. For each asynchronous data port, the stop bits, data bits and parity are user configurable. The SRU incorporates a built-in V.14 Async-to-sync converter to avoid over-sampling and consequently saves bandwidth. Asynchronous data circuits are converted to synchronous mode by the SRU card prior to multiplexing onto a WAN aggregate.
Sub-rate data ports are multiplexed into industry standard DSO formats. The user may specify the format of the DSO that the data port is assigned to. The choices are: DSO-A which allows only one data port to be mapped into the DSO and DSO-B which allows multiple data ports from multiple SRU cards in the system to be mapped into the same DSO time slot. If the DSO-B format is selected, then the user can specify the type of DSO-B format required (b-5, b-10 and b-20) and the sub-rate position that the data port will occupy within the DSO-B frame.
In b-5 mode, the DSO is divided into five sub-rate positions, each of which are occupied by a data port operating at
9.6Kbps, 4.8 Kbps, or 2.4 Kbps. Additionally, one or two 19.2 Kbps circuits are supported in b-5 mode. Each would occupy two of the five sub-rate positions. Additionally, data circuits running at 28.8 Kbps or 38.4 Kbps are supported in b-5 mode and will occupy three or four of the five available sub-rate positions. In b-10 mode, the DSO is divided into ten sub-rate positions, each of which are occupied by a data port operation at 4.8 Kbps or 2.4 Kbps. In b-20 mode, the DSO is divided into 20 sub-rate positions, each of which are occupied by a data port operating at
2.4Kbps.
In the application shown in Figure 14, the IMACS with the SRU card (on the right hand side) can either send each sub-rate on a separate DS0 (DSO-A format) or groom multiple sub-rate channels into a single DS0 (one of the DSO- B formats).