Does telnet service provide also historical quotes?
No. Live data only.
In sierrachart feed I'm using bitcoincharts only for historical data (except using "-w" option to disable websocket), but delaying makes big problem - once bridge download historical data (delayed) and then start streaming quotes using websocket (realtime), there remain 15min gap without quotes in datafile, forever. And currently I'm thinking about some clean solution...
And here's a trick. I don't store live data into the datafile but aggregate and cache only historical data (that are delayed). Live data are sticked to the historical ones and are eventually replaced when historical data become available. Take a look to the
source code.