Paradise P300 specifications Change, Tx/Rx, Service, Closed Network, No ESC, Plus ESC

Custom	This allows the operator to select a framing format based on the standard
	IBS/SMS or IDR definitions, but with non-standard or extra features such as
	Minimum overhead framing, or Multidestinational IBS. A description of the
	features and menus which follow this choice are in section 7.1.1 "Change, Tx/Rx,
	Service, Custom Menu" on page 133.

6.6.2Change, Tx/Rx, Service, CLOSED NETWORK

These screens are only shown if the Async ESC feature is available, standard on the P300-IBS and above.

Note: Closed Net Plus ESC is available with the P400 series modems, refer to “Closed Network Plus ESC via the Custom Service menu” in section 8.7.2 on page 148.

When Closed Net is selected the following screen is shown to allow the selection of normal Closed Network operation, or Closed Net Plus ESC:

Closed Network mode [?]:

1=No ESC (normal) 2: Plus ESC (min o/h)

	Change, Tx/Rx, Service, Closed Net, ESC Menu	9
NO ESC	The modem operates without adding any overhead to the data, this is `normal`
	Closed Network mode. Normal Closed Network adds no overhead to the data
	and is compatible with other closed network equipment such as the Paradise
	P200, and closed network equipment from other vendors.
PLUS ESC	The modem adds the minimum possible overhead to the satellite data (down to
	<1%) to support the async ESC rate you set. The exact overhead used can be
	viewed on the Info, View Config, Tx/Rx screens. It provides the following
	facilities:
	A variable rate ESC channel (up to approx 70% of main channel rate)
	An optional backward alarm facility.
	At rates of 32kbps and above it provides a synchronous scrambler to
	'replace the error multiplying V.35 normally used on closed network links.
	If used with Drop/Insert (Yes, Closed	Network with Drop/Insert), it

provides Timeslot ID maintenance across the link.

See the first few paragraphs of Appendix F where Backward Alarms, Synchronous Scrambling, and Timeslot ID Maintenance are discussed (in relation to an IBS/SMS carrier).

Note: As the overhead affects the final composite framed data rate, and the ESC

&backward alarm settings determine the required overhead, then for two modems to interwork the following parameters must match on both pieces of equipment:

Main data rate.

Async ESC Baud Rate, Character length and Parity. Backward Alarm option (ie both enabled or both disabled).

iBaseband modes (ie both Continuous Data or both Drop/Insert).

P300H P300 Ser es Modem Installation and Operating Handbook Page 55