Protocols
Part of Telegraph
Telegraph protocols are the agreed-upon rules that govern how messages are sent, received, acknowledged, and routed through a network of stations.
Why This Matters
Without protocols, a telegraph network is a collection of machines. With protocols, it becomes a communication system. The rules governing how operators call each other, how they acknowledge receipt, how they handle errors, how they prioritize traffic, and how they route messages through relay stations are what transform hardware into infrastructure.
The history of 19th-century telegraphy shows what happens without good protocols: competing telegraph companies used different codes, different message formats, and incompatible procedures. Messages stalled at company boundaries; errors propagated through networks; delays mounted at relay points. The eventual standardization of international telegraphy under the International Telegraph Union (1865, the precursor to today’s ITU) enabled global communication by establishing common procedures all stations could follow.
For a rebuilding community network, establishing protocols early — before the network grows and before bad habits become entrenched — is far easier than trying to retrofit standards onto a chaotic existing system. Good protocols are not bureaucratic overhead; they are the engineering discipline that makes the system reliable.
Calling and Answering
The basic contact sequence: the calling station identifies itself and the called station. The called station acknowledges. This simple exchange establishes that the channel is working, that both stations are present, and that communication is about to begin.
Standard calling format: “[Called station callsign] DE [Calling station callsign] K” — in Morse, this sends the called station’s identifier, the prosign DE (meaning “this is”), the calling station’s identifier, and K (meaning “go ahead” or “over”). Example: “NY DE PHIL K” (New York, this is Philadelphia, over).
If the called station is ready: “[Calling station] DE [Called station] K” — acknowledge and invite transmission.
If the called station is busy: “[Calling station] DE [Called station] AS” (wait), followed by the expected wait time if known.
If the called station does not answer after three calling attempts spaced 30 seconds apart: the calling station should wait 2–3 minutes, then try again. If repeated attempts fail: log the time and attempt, and try again at the next scheduled contact time or alert the network of the non-response.
Message Format and Precedence
Formal telegraph messages use a standard format that has remained essentially unchanged from mid-19th century practice to today’s amateur radio radiogram format:
- Preamble (message number, precedence, originating office, word count of text, date-time filed)
- Address (recipient name and location)
- Text (the message content)
- Signature (sender)
Precedence levels determine processing priority:
- EMERGENCY: Life safety. Handle and deliver immediately, regardless of other traffic. Interrupt ongoing messages if necessary.
- PRIORITY: Urgent but not life safety. Handle before routine traffic. May interrupt waiting routine messages.
- WELFARE: Messages concerning safety or health of individuals. Handle before routine, after priority and emergency.
- ROUTINE: Normal traffic. Handle in order received.
A receiving station processing a batch of messages should sort by precedence before delivery. Do not make a disaster victim wait for their emergency message to clear routine commercial traffic.
The word count (check) in the preamble is important: the receiving operator counts the words in the received text and verifies it matches the preamble count. A discrepancy indicates a transcription error — ask for a repeat of the message.
Relay Procedures
When a message must pass through an intermediate station to reach its destination, relay procedures govern handoff. The originating station passes the complete message (with preamble) to the relay station. The relay station acknowledges receipt, enters the message in its log, and as soon as the onward circuit is available, forwards it with its own handling annotation added to the preamble.
The relay station does not modify the message text under any circumstances. It may add handling information to the preamble (e.g., date-time received, relay station identifier) and must deliver the message to the next station in the route within a prescribed time (for emergency traffic, immediately; for routine traffic, within one hour or the next available opening).
When the final destination station receives the message, it acknowledges to the relay station. The relay station’s obligation is complete when it has confirmation of delivery. If delivery cannot be confirmed within a specified period (perhaps 24 hours for routine traffic), the relay station notifies the originating station so the sender knows the message is undelivered.
Error Handling
Errors in Morse transmission are corrected immediately. When the sender realizes a mistake has been made, send the error signal (eight dots: ········) to alert the receiver, then resend the correct character or word.
When the receiver is uncertain about a received character: send ”?” (the prosign for question) to indicate uncertainty. The sender will repeat the doubtful word or character.
After a complete message is received, the receiver reads back the entire message text for verification. The sender listens carefully and either confirms (“R” or “Roger”) or sends corrections. Only after confirmation is the message considered received. Never send a formal message without this read-back confirmation.
For messages sent in batches (a common practice when telegraph circuit time was expensive): number each message. At the end of the batch, the receiver confirms receipt by listing the numbers of all messages received. The sender notes any numbers not in the confirmation list and repeats those messages.
Traffic Handling Efficiency
An experienced telegraph operator handles traffic quickly and smoothly. Common efficiency practices:
Abbreviations: use standard abbreviations for common words and phrases. “ANS” for answer, “MSG” for message, “NR” for number, “WX” for weather, “HR” for here, “HW” for how, “UR” for your. These save time without ambiguity.
Q codes for operational queries: QTC = “I have [number] messages for you,” QRU = “I have nothing for you,” QSL = “I confirm receipt,” QRN = “I am troubled by static,” QRM = “I am being interfered with.” Sending “QTC 3?” asks “do you have messages for me?” A one-letter response codes an enormous amount of information.
Continuous transmission: where traffic volume warrants, a skilled sender can transmit a stream of messages without pausing for acknowledgment after each one. The receiver takes them down and at the end acknowledges all at once by message number. This fills the available circuit time productively rather than wasting it on overhead.
Scheduling: establish regular traffic times when specific circuits are open and all operators are prepared to handle traffic. Unscheduled contact attempts waste time if the other end is not ready. A schedule of daily contact windows for each circuit in the network ensures messages clear promptly and operators plan their time efficiently.
Network Administration
A growing telegraph network requires coordination beyond individual station operations. Network-level administration covers:
Circuit allocation: which pairs of stations maintain direct communication, and which traffic flows through relays. Direct circuits are faster but require dedicated line capacity; relay routing allows one circuit to serve many possible destination pairs. Map the network topology, identify bottlenecks, and plan route redundancy for critical links.
Time synchronization: telegraph networks relied on accurate time for message dating and for coordinating scheduled circuits. Each station should maintain a clock accurate to the minute, synchronized from a time signal (broadcast radio time signals, or a physical clock set from an authoritative source on a regular schedule). Log all events in UTC.
Record keeping: message logs at each station should be retained long enough to resolve any disputes about what was sent, received, or relayed. Minimum retention: 30 days for routine traffic, indefinitely for emergency traffic records.
Outage reporting: when a circuit fails, the station detecting the failure notifies the network controller and all affected stations through any available alternative route. Network controller coordinates repair or rerouting. No circuit should be offline without all stations knowing and adjusting accordingly.