How does Channel Box's Bypass Panel work?
The Chyron Bypass Relay Panel is an external device, powered by a USB connection from Channel Box. The unit is capable of having four streams of SDI or AES signal from the same device, running simultaneously, all of which will be switched out of circuit simultaneously. It is a mechanical relay bypass and will switch in under a frame. There is an unavoidable small glitch of less than a frame when this happens.
Each bypass panel can only be used with a single device. You cannot use a single panel with four circuits to give bypass support to four different Chyron devices. The purpose of the multiple inputs is to allow for a fill channel, a key channel (or a future second channel of graphics) and two AES audio channels. In this way, we can provide full audio and video bypass support.
The bypass panel comes standard with a single bypass relay card, which is installed into the body of the panel. Three additional cards can be added at additional cost to allow for the multi-channel bypass capability.
The advantage of an external panel versus the on-board bypasses that everybody else uses is huge. If hardware failure occurs, the user can physically swap out the unit without having to re-route or re-patch their program stream. They simply have to disconnect the unit, swap it out, and re-connect it. Their program stream remains intact throughout. This is not possible if the bypass is going through the box itself.
The panel can be sent into bypass mode in one of three ways:
- Loss of heartbeat from the host software (ie the Channel Box software). If the Channel Box software crashes, the heartbeat goes away and the panel goes into bypass.
- GPI Trigger: The panel can be switched into bypass mode via a remote GPI trigger.
- Locking Switch on front panel: The panel itself has a locking switch. Pull the switch out, and then move it to the bypass position.
To bring the panel out of bypass, all three of these factors must ‘line up’. For example, if the heartbeat does not exist from the software, switching the panel to the ‘in circuit’ setting will not bring the panel out of bypass.
The panel also features GPO support, which will communicate the state of the panel. For example, users can wire up a remote status panel with lights to indicate whether the panel is in circuit or in bypass. Three signals: State, State of FP Switch and state of heartbeat.
It is important to note the reasoning for the multiple trigger capability of the panel. You may ask why a heartbeat alone isn’t sufficient to put it into bypass. The reality is that Lyric is a multi-threaded application, meaning that the only way the heartbeat will disappear is if the thread in which it is running crashes. If a different thread crashes, it is entirely possible for the heartbeat to continue running. Hence the availability of a GPI trigger to put the system into bypass.
The bypass panel is currently only supported in Channel Box. DynaCrawl will be next in line for support, with the Lyric based products after that.
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