Serial Port Utility 6.6.4

Features

• Cloud Relay — use a serial port on another computer: The site machine turns on Cloud > Allow Cloud Relay; the operator picks Remote Serial (Cloud Relay) in the port list, chooses a port on one of the account's online computers and presses connect — from there it behaves like a local port: baud rate, data bits, parity, stop bits, flow control and DTR/RTS can be set remotely, the remote CTS/DSR/RI/DCD states are shown, and X/YMODEM transfers and Modbus work as usual. Both ends need nothing more than outbound Internet access — no public address, port forwarding or VPN. The picker says whether each computer is online and whether relay is allowed there; a port accepts one relay session at a time, the sharing side shows a status line while its port is in remote use, and a dropped relay is never redialled silently — connect again deliberately. Relayed traffic draws on the account's cloud traffic quota
• Remote use of a bridged port is visible on the sharing side: A bridge port served over RFC 2217 or plain TCP now announces clients arriving and leaving, the pane badge reads "in use by " and turns amber, and the serial parameters or control lines a remote client sets are logged line by line — the same rule Cloud Relay follows: a port driven from somewhere else must say so

Interface

• Remote serial shows what the remote is running: With "Keep the remote port's own config" ticked on the RFC 2217 and Cloud Relay pages, the five greyed-out local parameter rows are hidden — a disabled "115200" was too easy to read as a fact about the remote — and a read-only "Remote now" row shows the baud rate, data format, flow control and server signature the remote actually reports
• Cloud menu grouping: The Cloud Console master switch and the three Allow… consents are grouped, and the consents are disabled while the console is off — they all ride the Cloud Console channel, which the flat menu made look independent

Fixes

• Log written to a file called NULL: Until the first successful open the log file name is only a placeholder, and flushes triggered by pause, stop or a port opened by the reconnect supervisor did not recognise it, creating a file literally named "NULL" in the working directory. Those flushes now resolve the configured file name template first and log to the right file
• DTR lamp stuck grey: After selecting RFC 2217 or Cloud Relay in the connection editor and switching back to a local port, the DTR lamp stayed grey — which reads as "not asserted" — while RTS recovered; both now return to green
• DTR/RTS lamps grey for the life of an RFC 2217 client connection: With "Keep the remote port's own config" ticked the client never set DTR or RTS, so the server had nothing to confirm and both lamps showed "never asked" throughout. The first settings sync now queries the remote's current levels, so the confirmed state shows in both RFC 2217 client and Cloud Relay modes
• Command latency on the Cloud Console HTTP fallback: When the backend offers no WebSocket channel, queued commands now ride the heartbeat reply, cutting the worst-case wait from 30 seconds to one 20-second beat; a missing or stale cloud snapshot is re-uploaded as soon as the server asks for it, so picking a relay target no longer waits out a snapshot round trip