A trading floor has its own vocabulary, most of it undefined anywhere a newcomer
would look. These are the 35 terms Open Line uses without stopping to explain them.
- Turret
- The dedicated hardware console on a trading desk: a bank of keys, each one a standing, pre-provisioned line to a specific counterparty or channel. Pressing a key closes an already-open circuit; it doesn’t negotiate a new one.
- Perceptual latency
- How long before a human feels that a system responded, as distinct from how long the system actually took to do anything real. Can be engineered independently of the underlying network.
- Signalling latency
- The time a system spends negotiating a session before any media flows: finding the other party, agreeing a path, opening it. On SIP or WebRTC this is real, honest work; on a pre-provisioned private wire it was already done, once, long before anyone touched a key.
- Media latency
- Once a session path is open, the time before the first audio packet actually arrives at the far end. Usually short enough on its own not to be perceptible.
- SBC (session border controller)
- The device that sits at the edge of a voice network and brokers sessions crossing it: enforcing policy, translating between signalling dialects, and bridging a legacy PSTN/SIP trunk to whatever sits behind it.
- Hoot (hoot-and-holler)
- An always-on, open audio channel connecting a desk to a standing set of counterparties or an internal group, distinct from a phone call: nobody dials in or answers it, it’s simply on, and people tune their attention to it the way they’d tune to ambient noise in a room.
- Session
- A bounded communication with a start, a set of participants, and an end, each visible to the others as it happens. Almost every conferencing product is built around this shape, which is exactly why it’s the wrong default for a hoot.
- Channel
- An unbounded, always-on communication path that exists independently of who’s currently listening. Listeners attach and detach silently; the channel itself neither announces nor cares.
- SFU (selective forwarding unit)
- A media server architecture for multi-party calls that forwards each participant’s stream to the others without mixing them into one signal. Contrasts with Kurento’s pipeline model, which can mix inside the server itself.
- Key sheet
- The reference layout of a desk’s turret keys: which counterparty or channel sits on which physical key, and why. Historically a paper or laminated card kept by desk ops; a record of which counterparties earned a standing, zero-look position, not an arbitrary list.
- Recognition
- Identifying something already in front of you, such as a key in a fixed, memorized position. Fast, close to automatic, and largely undamaged by time pressure or stress.
- Recall
- Producing something from memory with nothing in front of you to confirm it, such as typing a counterparty’s name into a search field. Slower than recognition under the best conditions, and degrades further under time pressure.
- Relationship-carrying route
- A route that has to satisfy two separate firms who don’t trust each other’s engineering team by default, as opposed to an ordinary route that only has to satisfy one firm’s own operational judgment about its own infrastructure.
- Standing wire
- A durable, named entitlement binding two specific identities across a firm boundary, distinct from the SIP trunk or media route actually carrying its audio. Gets an admission-controlled, monitored capacity reservation, and any change to it requires a signed acknowledgment from an authorised representative on both sides before it takes effect.
- Comfort noise
- Synthesized audio, standard in VoIP, generated to fill the gaps silence suppression leaves behind so a quiet moment on a call doesn’t sound like a dead line. Carries no information; exists only to keep silence audibly distinct from failure.
- Sidetone
- A small, calibrated fraction of a speaker’s own voice fed back into their own earpiece. Originated as accidental leakage in analog handsets; has to be engineered back in deliberately on digital ones, or speakers unconsciously raise their voice, not trusting they’re being heard at all.
- Silence suppression
- A bandwidth-saving technique that stops sending real audio data during a detected silence, sending nothing (or a minimal comfort-noise descriptor) instead of a continuous stream.
- StatefulSet
- A Kubernetes workload type that gives each pod a stable, durable identity the orchestrator and monitoring can consistently refer to, as opposed to an ordinary Deployment, which treats its pods as interchangeable and disposable.
- Pod disruption budget
- A Kubernetes policy that caps how many pods of a given workload can be voluntarily evicted at once (during a node drain or cluster upgrade, for example), preventing a routine maintenance action from taking down every instance of a stateful workload in the same pass.
- preStop hook
- Code that runs the instant a Kubernetes pod is marked for termination, before it’s actually killed. Used to stop a pod from accepting new work immediately while letting existing work finish or hand off during its termination grace period.
- Line card
- The physical circuit card in an old telephone exchange or PBX that terminated one specific line. Doubled as identity by construction: changing which desk a line served took a technician physically patching it, the turret vendor’s field engineer or the bank’s own telecom ops rather than a public phone company, so identity never changed without a second party’s hands on it. That friction was accidental, not a designed safeguard.
- Relying party
- A system that verifies identity assertions against someone else’s trust anchor without being able to issue or vouch for those identities itself. Infinet is deliberately a relying party on both sides of a standing wire: it can check a signature, and it can never mint one.
- Attestation ledger
- A customer-facing, cryptographically signed, append-only record of every material change to the guarantees a customer is paying for. Proposed as the software replacement for the thing a physical box used to provide for free: proof, continuously, that a vendor’s promise is still true.
- Leg
- One participant’s connection into a call or a channel. A two-party call has two legs; a hoot with thirty listeners has thirty. Capacity in this book is counted in legs rather than calls, because the cost of a mixed channel falls on the listeners rather than on the talkers.
- Position
- One seat on a trading floor and the equipment on it, together with the entitlements attached to whoever is sitting there. A position is not a person: people move between positions, and the whole of the identity argument turns on the record knowing which was which. A position typically renders several channels at once, so a floor of two thousand positions carries considerably more than two thousand legs.
- Desk
- Confusingly, three things. A physical seat, a group of people who trade the same product (the rates desk, the FX forwards desk), and the business unit that owns their profit and loss. Where it matters, this book means the group of people.
- Book
- A trader’s set of positions and exposures, the thing they are responsible for. Somebody covering another trader’s book is standing in for them.
- Private wire
- Used interchangeably with standing wire: a permanently provisioned point-to-point connection between two firms, always up, requiring no dialling and no setup. The oldest and most jealously defended object on a trading floor.
- Wall-crossed
- Formally brought over an information barrier and made an insider for a specific transaction, with the crossing recorded. Someone who is wall-crossed is permitted to hear things their colleagues on the other side of the barrier are not.
- Dealerboard
- Another name for a turret. The two are used interchangeably in the industry and occasionally in the same conversation.
- Barge
- Joining a call already in progress without being invited, usually by a supervisor. One of the turret behaviours that exists because a trading floor has a hierarchy of urgency.
- Priority ring
- An incoming call that announces itself differently, and can push past whatever the position is currently doing, because the caller is entitled to interrupt.
- Forced release
- Dropping somebody else’s call from a position without their agreement, usually to free a line or remove a person who should not be on it. The most invasive of the turret behaviours and the one hardest to justify to anybody outside the industry.
- Hands-free answer
- A position that answers automatically, opening the speaker without anybody pressing anything, so the caller is simply speaking into the room.
- The open, the close
- The beginning and end of a trading session. Both are the busiest and least forgiving moments of the day, and most of this book’s operational arguments are really arguments about what happens at the open.