Premier Mounts CDM-600 specifications Esc++, Overhead Details

Chapter 13. ESC++

13.1Introduction

The ESC++ mode of operation is a new, closed network frame structure which combines Automatic Uplink Power Control (AUPC) with a high speed asynchronous order-wire channel. The AUPC works identically to that offered with EDMAC and D&I++ framing, but is not compatible with either. This is because ESC++ framing uses a different overhead percentage than the other closed network framing modes.

In order to use this feature, Firmware Version 2.0.1 (or higher) must be installed.

13.2Overhead Details

Baud rates from 1200 to 38400 bits/sec are offered using RS-232 format. As with the main remote port (P4B), three data formats are available: 8N1, 7E2 and 7O2. Pins 5 and

6 of P3A are the input and output, respectively, for this data channel. Because 38.4 kbaud is the maximum rate available, the actual overhead percentage for ESC++ framing changes as the data rate increases, thereby saving bandwidth at high data rates. The added overhead is as follows:

Data rate		Overhead ratio (percentage)
64 kbps to < 768 kbps		19/17 (11.76%)
768 kbps to 1.5 Mbps		12/11 (9.09%)
> 1.5	Mbps to 2.5 Mbps	29/27 (7.4%)
> 2.5	Mbps to 7 Mbps	19/18 (5.56%)
> 7 Mbps		64/63 (1.58%)

Note that 64 kbps is the minimum data rate allowable with ESC++. Depending upon code rate and modulation used, the modem’s maximum data rate of 20 Mbps may be used with ESC++. In all cases, if the Reed-Solomon outer codec is used, the 126/112 ratio is employed with ESC++. The new frame structure may be used with any FEC codec type available with the CDM-600.

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