Nevion HDSDI-CHO-2x1 - Manual (Page 4)

HDSDI-CHO-2x1 Rev. G
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1 Product overview
1.1 Product description
Figure 1: HDSDI-CHO-2x1(-PB) functional overview
The Flashlink HDSDI-CHO-2x1 is a serial digital video 2x1 change-over module providing
high performance line protection for various signal formats from 1Mbps up to 1485Mbps. The
unit can be configured to perform cable equalizing and re-clocking of SMPTE 292M, SMPTE
259M and DVB-ASI signal formats. The switching criteria can be selected to be based on
loss of input signal or loss of lock (re-clocker). The switch can either be latching or non-
latching (in loss of lock mode, only latching switch is available). It is also possible to control
the switch with GPI inputs, with the GYDA system controller or with the open protocol RS422
interface.
The two inputs typically provide automatic cable equalizers for up to 250 meters of cable
(Belden 8281A at 270Mbps) with a 2 x 1 switch in front of a re-clocker with 4 outputs. The re-
clocker supports the bit-rates; 143, 177, 270, 360, 540 and 1485Mbps. For other rates, the
re-clocker automatically switches to bypass mode and the HDSDI-CHO-2x1 will work as a
non-reclocking 2x1 change-over unit with cable equalizer. The HDSDI-CHO-2x1 also has a
special DVB-ASI mode, enabling all possible rates including empty transport streams with
only K28.5 padding packets. 2 outputs are non-inverting to support DVB-ASI compatibility.
The HDSDI-CHO-2x1 is designed for various line protection applications for studio, campus,
broadcast and telecom.
New in firmware version 2.0.0 or newer: When latched to standby input, latch will not hold
against missing signal on standby input if the signal on main input has been restored. Also, a
secondary timer has been added, which handles debouncing of the “signal on main input
returns” condition. The primary timer handles debouncing of LOS on both main and standby
inputs.
1.2 Product versions
HDSDI-CHO-2x1 2x1 HD/SD-SDI changeover
HDSDI-CHO-2x1-PB 2x1 HD/SD-SDI change over with passive bypass