Timenet RS-485 serial with Zilog Z80 ISA 8 bit - Page 1
Forum section: electronics / general

author: MrMobodies
author_rank: Super Contributor
timestamp: March 09, 2021, 02:30:45 am
content: I had this in my collection and forgot about it for a long time.I think plugged it in but nothing appeared but may try again.Can someone identify what this might have been used for?

author: retiredfeline
author_rank: Frequent Contributor
timestamp: March 09, 2021, 04:00:11 am
content: Comms card for an ISP of a bygone era? Looks like there's also a parallel port too.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 09, 2021, 11:26:27 am
content: Think that's a bog standard DB-25 serial, actually -- the top right chip is a RS-232 transceiver in fact.Can't quite make out the light-colored DIPs, thought they were resistor packs at first, no idea why those would be there -- on second thought they're probably optos, and the RS-485 is isolated -- there's a transformer (actually probably a DC-DC converter module) there too. Guessing just galvanic isolation, certainly doesn't seem to be any special clearance around it. Not clear how the PC bus (ISA?) and Z180 bus interface; maybe that's integrated into that UART chip too? Maybe it's shared and the PC just takes priority (inserting wait states or whatever as needed), dunno. Nice big RAM on there, guessing mostly for buffering.Tim

author: CJay
author_rank: Super Contributor
timestamp: March 09, 2021, 11:51:56 am
content: Quote from: T3sl4co1l on March 09, 2021, 11:26:27 amLooks like an opto-isolated RS485 and RS232, the SCN chip is a dual UART. The ROM contents might tell more but probably won't be accessible from the ISA bus so it's need to be pulled and read.Real time clock on there too. Interesting card, maybe it's function is given away by the name and it's a time sync card on some sort of multi-drop RS-485 network?

author: joeqsmith
author_rank: Super Contributor
timestamp: March 09, 2021, 12:26:14 pm
content: First Google hit.The JVF TIMENET product range provides Time Management facilities ranging from a simple 25 employee timeclock to large WAN based multi-site systems with fully integrated access control and data capture facilities.All our systems operate seamlessly over RS485, modems, LANs and WANs with remote setup and reporting.https://timenetsystems.co.uk/

author: CJay
author_rank: Super Contributor
timestamp: March 09, 2021, 12:33:45 pm
content: Quote from: joeqsmith on March 09, 2021, 12:26:14 pmAwhhh, spoiled all the funMy Google Fu must be weak today, I didn't get a result but I did only make one search

author: m k
author_rank: Super Contributor
timestamp: March 09, 2021, 06:28:29 pm
content: Battery backed settings?

author: MrMobodies
author_rank: Super Contributor
timestamp: March 09, 2021, 06:44:35 pm
content: Actually the the board was made in about 1994 website looked like opened in 2013:https://whois.domaintools.com/timenetsystems.co.ukQuoteI think that website might a spin off from this one:https://www.jvf.co.uk/https://whois.domaintools.com/jvf.co.ukQuoteThey both share:QuoteEdit:About 118 millivolt left in that 3v NiMH battery.

author: TomS_
author_rank: Frequent Contributor
timestamp: March 15, 2021, 08:19:50 pm
content: You could try emailing them and asking for datasheets etc, especially since it looks like this should be well and truly a retired product.I tried this recently with some random cards I picked up, and sure enough the company was still around and they sent me everything they had at hand.Don't ask, don't get is my motto! 😄

author: MIS42N
author_rank: Frequent Contributor
timestamp: April 12, 2021, 07:56:38 am
content: The cream topped ICs are 6N137 optocouplers. One per package.

author: woofy
author_rank: Frequent Contributor
timestamp: April 12, 2021, 09:28:11 am
content: Quote from: T3sl4co1l on March 09, 2021, 11:26:27 amIt looks like the ISA bus is buffered with an HC574 latch. The Z180 writes to the latch and the ISA reads it in its own time. The chip to the right of the HC574 (U16/18?) is probably another one to latch incoming data. The SCC2692 looks to be sitting on the CPU bus. However, I do wonder why the SCC2692 is there when the Z180 has two UARTS built in.