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--- telephony:td816bx_hardware [2026/04/01 11:45] – prppedro
+++ telephony:td816bx_hardware [2026/04/01 17:57] (current) – prppedro
@@ Line 5: / Line 5: @@
 {{ :telephony:toshiba_tmp68301af-12_cpu.jpg?200|}}
-This system got no more than a few hundred KB's of RAM. System configuration is stored on a EEPROM. The CPU is a 68k chip (yeah, same as Macintosh computers and several embedded devices of the era). This unity got the TMP68301AF-12 variant of that chip, manufactured by Toshiba.
+This system got no more than a few hundred KB's of RAM. System configuration is stored on a EEPROM (I mean... is it? Couldn't confirm). The CPU is a m68k chip (yeah, same as Macintosh computers and several embedded devices of the era). This unity got the TMP68301AF-12 variant of that chip, manufactured by Toshiba.
+The ROM complex is detachable, for reasons I deem not completely clear, since those chips are already seated on sockets. See below for more information on that detachable board.
-The ROM complex is detachable, for reasons I deem unclear, since those chips are already seated on sockets. See below for more information on that detachable board.
 ## ROM version
@@ Line 32: / Line 33: @@
 As for the Caller ID card, this is an adventure on it's own, and this KX-TD193DX card is basically the same card (TA123293) used by TA1232, the non-DPITS, older version of TD1232, from what I gather. TA1232 itself is a eerily similar project. I'm discussing those topics [[telephony:ta1232_td816_td1232_hw_arch#caller_identification_card|on a different article]].
+## Upgrade path
+According to information from {{ :telephony:td1232-816upgradelist.pdf |this document}}, TD816 -1 units cannot be upgraded to level two. I assume that's due to the 8 MHz CPU being soldered to the motherboard, since the same upgrade is possible on TD1232. Unless TMP68301AF-12 really turns to be a 12 MHz (and operating at 12 MHz), we're dead in the tracks here.
+If the CPU is really a 12 MHz one, we have other stuff to consider:
+### RAM
+Either we got 256 KB or 320 KB, unclear without specific schematic for this unit, we may be able to upgrade the DPIP-32 packages to a 4Mbit chips, bringing the RAM in the daughter card to 1 MB total, which is hella expensive;
+### ROM
+The 27C040Q-120 ROM is a 4Mbit (512Kx8) UV-EEPROM chip, we have one for the main software (P401A) and other for whatever it is (P402A), we may want to buy another EEPROM to keep that one as backup, and a larger one at it, since I think newer versions uses more than 512 KB of space;
+###Firmware
+It's nearly damn impossible to find firmwares for that thing, I was able to track some of them, but can't even say if they're adequate for my unit.
 ## ROM/RTC clock Board
@@ Line 77: / Line 93: @@
 This makes the system kind of an hybrid between -1 and -2, hardware-wise. The CPU smells like 12 MHz, judging by it's model suffix (the datasheet for it mentions 8~16 MHz sub-models), but the amount of RAM is very far behind even other models of -1 (cf. «ROM mysteries» above.)
+Anyhow, [like I've posted on Sundance Communications](https://sundance-communications.com/forum/ubbthreads.php/topics/647458/toner), the oscillator seems to be doing 8 MHz, so I don't know if the CPU is really operating at 12 MHz.

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