Occurrence of this PCB

The HT486 PCB does not carry its name; it is used in the following device models:

• HandyTone 486

This manufacturer also produces other models.

These devices are end-of-life at GrandStream.

Components found

• DSP system-on-chip: TMS320VC5402, with an extensive user manual. The PGE100 version is green, in that it is RoHS-compliant and uses no Pb/Br.
• Flash memory: 512k x 16, or 1024k x 8: MX29LV800BBTC-70. The cycle speed is 70 ns, making this flash suitable for running code directly. This means that smaller RAM will do.
• Static RAM: 256k x 16, or 512k x 8: IS61LV25616AL-10T.
• Ethernet: RTL8019AS and, unlike later GrandStream devices, not a switch to accommodate the second ethernet link but two of those ethernet controllers. The RTL8019AS is an NE2000 clone, albeit a bad one according to the Linux kernel. It does not really matter; at least example code is available in that kernel, and actually uIP has already been ported to these chips before.
• Codec: Si3210-KT programmable CMOS SLIC/Codec with ringing/battery voltage generation. Interfaces to a locally attached analog telephone and supplies it with the voltages and tones needed to mimic an analog switch.

Connectors found

These are described centrally in more detail:

• JP1 is not named on the PCB, but has 16 pins and is likely to support JTAG as well as synchronous serial communication and bootloading.

The JTAG/bootloader connector used in these Grandstream phones is a 16-pin connector. Its solder islands are open on the PCB, so soldering in a 0.1" pitched two-row pin header is easy.