Introduction: Setting up an 8-port SMS modem pool on Windows or Linux starts with host port recognition, SIM channel mapping, and a clean AT response before any SMS software connects. The hardware supports both operating systems, while YX provides its driver, software, and primary technical service for Windows.

You have an 8-port SMS modem pool ready, and Windows or Linux must see all eight channels before software can connect. YX primarily provides driver, software, and technical service for Windows; Linux support refers to the hardware and standard serial/AT-command compatibility, and YX does not provide Linux drivers or software. The first practical hurdle is whether the host sees eight stable serial channels, whether each channel maps to the right SIM slot, and whether a basic AT command returns a clean OK. Get that chain right, and SMS Caster or SMS Deliverer can connect with far less guesswork. If port recognition or SIM mapping is wrong, later errors often look like software problems even when the real issue sits at the serial layer.

How an 8-Port Modem Pool Appears to Windows and Linux

A YX 8-port SMS modem pool uses one USB connection to the host. Inside the enclosure, that single USB link fans out into eight serial channels, each tied to a SIM slot and a 4G LTE modem or associated GSM modem module. Linux usually exposes those channels as ttyUSB nodes, such as ttyUSB0 through ttyUSB7, while Windows usually creates virtual COM ports, such as COM3 through COM10. The exact numbers depend on what else is already connected to the machine, so treat port names as temporary until you map them. That naming detail matters because your SMS software does not send through “the modem pool” as one abstract device. It sends through a specific serial port. If COM5 maps to SIM slot 2 today and changes after a reboot, your sender ID, delivery reports, and campaign routing can move to the wrong channel. The Linux kernel USB serial documentation explains how multi-port USB serial devices mount as ttyUSB nodes, and Microsoft serial driver documentation explains how Windows manages virtual COM ports. Together they describe host behavior; the practical task is to build a port-to-SIM table for the YX unit. The YX product supports Windows and Linux at the hardware and standard AT-command level. YX primarily provides Windows drivers, software, and technical service; Linux drivers and software are not provided by YX. Android compatibility may depend on the host and application environment. IMEI change is included as a hardware channel configuration capability, which helps when you want to label and manage channels during testing. The goal is simple: know which host port belongs to which physical SIM slot before any bulk sending starts. Once that table is stable, each channel has a known identity, and troubleshooting stays focused on the right layer.

Preparing Host Drivers, Port Mapping, and AT Command Testing

After the host recognizes the device, work through driver checks, port mapping, and AT command testing in a fixed order. The driver and software instructions below are primarily for Windows. On Linux, YX does not provide drivers or software; use the operating system's own serial support and your own compatible tools if you choose to integrate the hardware. The four steps below apply to a small test bench and to a rack-mounted deployment. Each step checks a condition that will otherwise become a confusing failure later.

Confirm that all eight ports enumerate. On Windows, open Device Manager and look under Ports (COM & LPT). On Linux, check kernel messages with `dmesg | grep tty` or list `/dev/ttyUSB*`. If you see seven ports instead of eight, the host is not ready for an 8-port SMS modem pool. Check the USB cable, avoid an unpowered hub, confirm the power supply, and verify that the driver loaded. A missing port now becomes a missing SIM channel in production.
Map each port to the intended SIM channel. Label every SIM slot with a number, then match it to a COM port or ttyUSB node by testing one channel at a time. The condition to check is stability: if the numbering changes after you unplug and replug the USB cable, your mapping is not reliable yet. On Linux, udev rules can create stable names, but YX does not provide Linux driver packages or software. On Windows, you can keep the same USB port and review assigned COM numbers. A wrong map sends messages from the wrong SIM, which is hard to spot until customers reply to the wrong number.
Test basic AT responses on each mapped port. Open a serial terminal at the baud rate given in the printed manual, type `AT`, and expect `OK`. Then check SIM readiness with `AT+CPIN? `, signal with `AT+CSQ`, and message mode with `AT+CMGF=1` for text mode. Message-service commands such as `AT+CMGS` follow the standard AT message-service command set, but module command support can still vary by revision. If `AT` returns nothing, you are likely on the wrong port or baud rate. If `AT` returns `OK` but the SIM command fails, the serial layer is fine and the SIM or registration state needs attention.
Connect SMS Caster or SMS Deliverer only after serial access is stable. The software should see the same mapped ports and accept the same baud and message mode you tested manually. The condition here is repeatability: close the serial terminal, open the SMS tool, and confirm it can query each channel without timeouts. If the software connects but sends fail, return to the port-to-SIM map and AT responses before reinstalling anything. This order keeps the problem inside one layer instead of turning it into a guessing game across driver, modem, SIM, and software.

Connecting SMS Caster or SMS Deliverer and Asking for Remote Help

For Windows, SMS Caster and SMS Deliverer are the practical software layer for this hardware and are the main software path supported by YX. Linux drivers and software are not provided by YX, so Linux users must arrange their own compatible serial tools and integration. Their connection depends on two things: the correct port-to-SIM mapping and stable serial access. Set the software to the mapped ports, use the baud rate from the printed manual, and start with a small test send on one channel before you open eight channels at once. If the first channel works and the second does not, the issue is usually in the map, the SIM state, or the port configuration rather than the whole modem pool. On Linux, ModemManager can claim a newly detected modem and hold the serial port. ArchWiki’s mobile broadband modem page is a useful practice reference for udev rules, ModemManager behavior, and USB modem handling. Treat it as a Linux practice reference only. YX driver files, product-specific software, and primary technical assistance are provided for Windows; YX does not provide Linux driver files or Linux software. On Windows, a COM port that disappears after reboot usually points to driver behavior, USB power management, or a different physical USB port. Record what the host does and compare it with the manual instead of forcing the same settings blindly. When driver behavior differs by OS build, USB controller, or module revision, product-specific steps are more reliable than guessing. The printed manual and remote technical assistance are the fastest path for those steps. Before you contact support, collect three things: your OS version and build, the full list of detected ports, and the exact AT responses from one working channel. That lets support check the driver layer, IMEI channel configuration, and SMS software settings against the actual YX 8-port SMS modem pool you have on the bench.

Conclusion

Setting up an 8-port SMS modem pool is a short chain: one USB connection creates eight serial channels, Linux shows ttyUSB nodes, Windows creates virtual COM ports, and your job is to map those channels to SIM slots before you test AT commands and connect SMS software. The YX pool supports Windows and Linux at the hardware and standard AT-command level, while YX primarily provides Windows drivers, software, and technical service. YX does not provide Linux drivers or software. The pool also offers IMEI channel configuration and Windows guidance for SMS Caster or SMS Deliverer. Work in order, keep a written map, and use the printed manual or remote assistance when a driver or module revision behaves differently.

FAQ

Q：How do I know if Windows or Linux has recognized all eight ports?

A：On Windows, open Device Manager and count the new entries under Ports (COM & LPT). On Linux, run `dmesg | grep tty` or list `/dev/ttyUSB*` and count the nodes. You should see eight separate serial channels after the YX 8-port SMS modem pool is connected and powered. On Windows, use the YX-provided driver and supported software path; on Linux, YX does not provide drivers or software. If you see fewer, check the USB cable, power supply, hub, and driver before testing SMS software.

Q：Which AT command should I test first after connecting the modem pool?

A：Start with `AT` and expect `OK`. That confirms the serial port, baud rate, and basic modem response. Then check SIM readiness with `AT+CPIN? `, signal with `AT+CSQ`, and message mode with `AT+CMGF=1`. Only after those return sensible results should you move to `AT+CMGS` or connect SMS Caster and SMS Deliverer.

Q：Can SMS Caster and SMS Deliverer connect after the serial ports are mapped?

A：Yes—on Windows. Once all eight ports are stable and mapped to the right SIM channels, SMS Caster and SMS Deliverer can use those ports for sending and management. YX primarily supports this Windows workflow. Linux drivers and software are not provided by YX, so Linux users must provide their own compatible software and integration. Use the same baud rate and message mode you tested manually, and start with one channel before opening all eight. If connection fails, recheck the port map and AT responses before changing software settings.